At eight months pregnant I was in the emergency room. Although I curled around my ever-expanding belly for comfort, the visit had nothing to do with my baby. I was having my father evaluated for a psychiatric stay: his fifth in five months.

I felt my daughter hiccup within my ribs, grounding me to myself as I answered the triage nurse’s questions about my father’s mental state, personality and health history. As I spoke to the nurse, my dad lay on a hospital bed, curled in the fetal position.

Although this baby would be making me a parent, I had been mothering for years.

I can’t remember exactly when I first realized that I was acting as a parent to my father. Was it when I pleaded with him to adhere to his medication schedule? Was it when I indulged in his creative fantasies, hoping that by playing along with his desires I could inspire some healing? Was it when I asked him to take a shower and change the sheets on the bed that he remained in day after day? Personal hygiene is really important, I reminded him.

Whenever it was, I know that the realization came with a healthy dose of bitterness. Most people expect to care for ailing parents at some point. In an ideal world, after your parents have helped you raise your own kids, roles are reversed and parents become the recipients of care. As parents age, children often provide comfort, love and compassion toward the end of life, and guide their parents through death with dignity.

I resented the fact that in addition to kick-starting my own adult life, I was focused on saving my father's.

However, in my family, mental illness had pushed up the timeline. I was just 18 when my father had a massive episode of bipolar disorder, which rendered him unable to work, live alone, or complete simple daily tasks. Although he didn’t live with me, by the time I was in my early twenties my mind was preoccupied with my father’s care. I encouraged him to seek support for his illness and helped secure housing for him when he was no longer able to live with family. Through ten years of chronic depression I did everything and anything I could to care for my dad, and fight for his recovery.

The burden of taking care of a parent was intensified by the timing: I resented the fact that in addition to kick-starting my own adult life, I was focused on saving my father’s. It was difficult to be present with the challenges of starting a career and a family when my mind often wandered to my father’s challenges, which seemed so much greater.

Fifteen years ago, before my dad became ill, he had taught our family the value of meditation and mindfulness. Before meditation became mainstream, my father would wake his four kids each morning and lead us in a meditation that only ended when the neighborhood kids knocked on our door, collecting me and my siblings for the walk to school. During my dad’s illness, I tried to remember the lessons he had taught me about being present and accepting things as they come. It was hard to do, and I was sad that I could no longer turn to him for advice on these matters.

When mental illness, or any other chronic disease strikes a parent, the role reversal can be one of the hardest things for a child to accept. Not only does the child lose the guidance and support of a parent, but they also must assume a new care-taking role. As I planned my wedding, for example, I knew that because of my father’s illness he would be unable to help with the logistics of the day. In addition to losing that support, I also spent a large amount of time considering what would make the day most comfortable and manageable for him. In the end, those accommodations made the day wonderful for both of us.

Of course, none of this is easy for the parent either. No parent wants to feel that they’ve failed their child, and few want to take direction from the people who they are supposed to be teaching. Of all the writing I have done about my father and his illness, the only time he has ever reproached me was about a simple line in a much larger story, referring to him as “the man to whom I often feel I am the parent”. His comment prompted a discussion about how his illness had changed our relationship, and we were both able to acknowledge the emotional toll that this role reversal took on the us.

Like any parent, I have had lots of frustrations over the course of caring for my father. I hated when he brushed my ideas aside, or ignored my seemingly simple requests. I prayed that he would gain more independence and was consumed with worry when he did. You just can’t understand, he told me once. It’s a phrase any parent hates to hear, and it just highlighted my helplessness in the situation.

Over years and years of chronic hospitalizations with no progress, I was worn down. That day in the emergency room, I resented that instead of embracing my last month of pregnancy I was distracted by the all-consuming worry I felt for my father. This isn’t how it’s supposed to be, I thought. He should be supporting me right now, not the other way around.

I chose to let go of my expectations of what our parent-child relationship should be.

Yet, it was actually becoming a parent that helped me to accept the role reversal in my relationship with my father.

Motherhood, people kept telling me, is the most selfless kind of love. Sure, it’s amazing, but it’s lonely and exhausting, and you get little in return. Each stage of parenting, they said, is a new challenge. The kids will push you to the brink, and make you feel as if you are on the most beautiful and tragic ride of your life. Never, people warned, be lulled into believing that you are in control.

All of which described my relationship with my father and his bipolar disorder perfectly. I realized that in order to be the best support I could for my father, I needed to choose to let go of my preconceived notion of our relationship, and live it as it was day to day.

When my daughter was born she required so much work and was able to give nothing in return. Yet I loved her fiercely. I realized that if I were truly to parent my father, I had to do it selflessly. I chose to let go of my expectations of what our parent-child relationship should be, and accept it as it was.

That’s a parenting lesson that will last me a lifetime.