To be brutally honest, I didn't enjoy it until my older dd was about a year old. In fact, her first year was the worst time of my life. I felt awful about it, and worried about my ability to parent, and if my feelings would harm my dd, and what it meant about me as a person. It was so different than I expected. Like you said, I felt like I was babysitting someone else's child that whole time. Thankfully, something happened hormonally or something after she turned a year old, and I started to feel differently. And over time, things became wonderful and have stayed that way. Luckily, I haven't gone through that with my second, and I think it's largely because I had more realistic expectations, as did my dh, and therefore I was more prepared and he was more supportive this time around. But I will say it took me 7 years before I was ready to have a second one.
All I can do is give hugs and tell you that it will get better. Hold on. You say you don't think it's depression, but I would talk to someone, your doctor or midwife maybe, and just go through it with them. Just to look at that avenue. And really just hold on and accept help when given, nap when the baby naps, and don't worry too much about housework for a while.
I've learned that I am just not a baby person. I love my daughter but I did not enjoy this past year. I yearn for her to be a bit older.
I also want to add that I am going through depression, and my whole "outlook" has improved with medical help and talk therapy. It's okay if you are depressed, just get the proper help for yourself (and husband).