OP, sorry you're struggling, but it's early days yet. Don't write yourself off as not enjoying parenthood/not being up to it.
On mat leave I found things much harder if I was stuck in the house all day as the time dragged.
These are the things that helped me, they may or may not work for you:
-Getting out for at least one walk a day, for at least an hour, often longer. I spent lots of time just walking aimlessly with the pram. It always sent DD to sleep so I could enjoy a bit of peace. I liked exploring streets I'd not been to before, people watching and having a nosy at the houses and buildings I passed.
-The sling was a saviour. I'd pop DD in it and she'd be asleep in no time. Or if she didn't want to sleep she'd just hang out in there and watch what was going on. It stopped me being a slave to naps because I could go out whenever I wanted or get on with stuff around the house rather than stand over a cot shushing. I'd often take myself off to a local cafe with a book and sit there while DD napped in the sling. If she was awake I'd pop her in a high chair and we'd eat together.
-I joined baby groups, which helped to break up the week and gave me something to look forward to. I made sure I had something to go to most days. There are lots of groups that are free or low cost, are there any in your area you could join? This might help with making friends too.
-From when DD was about 4 months I started leaving her with DH once a week and re-joined my sporting hobby. It was a much needed break from all the mum stuff and helped me feel like myself again. Do you have any hobbies you could do for even an hour a week?
-No matter how tired I was, always made sure to read a bit before bed, even if I could only manage one page. It rounds off the day nicely and offers a bit of escapism from the drudgery.
It's not always been easy and plain sailing, but those things really helped me and now that DD is at nursery it's easier still. I hope things improve for you, hang in there!