I don't really believe in losing yourself to motherhood. At least not anymore than you lose yourself to anything in life.
Let me clarify. As a fairly new mama there have been times when I've felt like I've 'lost myself.' But that usually happens when I start to think I'm meant for something super awesome. It's a classic grass is greener on the other side type thing. Granted this happens in my darker moments when motherhood feels decidedly not awesome. But I think this is a mistaken way of thinking. I am not the activities I enjoy, I am not knitting, running, reading, ultimate frisbee, or stout beer. These things are good and enriching but they don't make me who I am. It is still important I do them for my own good, but if I never knitted again I wouldn't be less of myself.
My point is I am most myself when I bring myself, all my gifts and weirdnesses and also faults into what I am doing...into my duties, my conversations, my work, my play, everything. I may have to spend my entire day typing on the computer and feeding Luthien, and doing laundry, but if I do these as myself bringing myself into them for love of my family and of myself, I do not lose myself in them. For instance, yesterday evening Luthien was kind of a nutcase. She was crazy and I was feeling like losing it. So I just started hanging with her and pretty soon we were spinning in circles in the living room and laughing, getting dizzy and falling down. I was still in full blowing mom mode, but I felt completely myself too. I will spin around in circles with my kid even if I look like an idiot and this is a good thing about me.
So in all that is crazy about parenthood, I contend it is possible to bring your selfhood into it, and let it thrive there. If that means you sing a song about pooping to keep your kid entertained while changing their diaper that totally works. Making time for ourselves individually is important, but so is realizing that you don't cease to exist, to have personality when you are doing your regular parenting work.