I felt the same way for the entire first year of my daughters life. Frequent regret. It was a very hard adjustment into motherhood for myself. Some women talk about love at first sight with their babies but the first time my daughter was handed to me after giving birth, I felt fear and dread. My family and SO's were delighted, and because I was a stay at home mother-my SO didn't have to deal with (what I classified as) the baby 'hardships' and he didn't feel troubled. I considered, if the family circumstances were different, maybe I'd suggest adoption or let her be raised by her grandparents. I was ashamed. I felt SO and I argued a lot. I was always depressed and being a mother felt like a great burden. Suicide was in the back of my mind, always there.
I mentioned this, as casually as I could muster, to the midwife at a post-partum appointment but I think she just forgot by the end of the appointment because she didn't prescribe anything and I was too embarrassed to bring it up again.
I didn't enjoy that first year. I still do not miss it or think fondly of it.
I pushed on, because I felt the only other option was suicide and it'd be leaving my SO and daughter and though I considered they'd recover in time, I didn't want to put the hurt or loneliness there.
After the first year, things picked up. She could be interacted with more, gave more fulfilling reaction, sleeping at night got better. I guess the less dependent she was for every minor thing, there was a relief. It got even better after she turned two. We could "play together", and visit petting zoos, playgrounds, go to the beach. She became more social with others (whereas being very shy before). At two and a half, I got a part-time job outside of the home and my own feelings also improved dramatically. It was nice to be expected somewhere else to get non-kid tasks done. A change of scenery... She's three now, and we can hang out, have conversations, go on little adventures, she's interested in learning and making friends with other kids.
That entire first year was, to me, brutal and bumpy. But it got better and has certainly gotten more-so better the older she got.
I suppose I don't recommend just waiting it out- a year can drag on if you're unhappy, it was a long year- and talking to a doctor would probably help, but as someone that was too ashamed to pursue help, I wanted to share a later turn around.