YANBU. All kids are different and it can be really tough.
Agree you sound like you need a break if you can manage to work out how to get one. Even one hour away from your responsibilities/on your own might help? (Go out for a walk, a coffee?)
It's the lack of a break which can wear you down. So the more breaks you can wangle the better.
I could never have managed my 1st born without help/breaks. He wouldnt sleep more than 10 mins at a stretch, cried and cried and generally terrorised me! (Even both my DM and my MIL found him v difficult, which made me feel a bit better/less of a failure!)
My 1st born is now 23 and a v nice young man ..... living, working and enjoying his single life in a different country. And not terrorising anyone! (Who'd have thought?) I am very proud of him.
So plse don't imagine all mums sail through the early years. Some do, many don't. (I didn't!)
I was exhausted and depressed for at least 6 months after my 1st, & then I decided to get pregnant again, as I didnt want him to be an only child and I feared I would never have the courage to do it again if I waited. And somehow having a 2nd child helped! (Hormones? An early playmate for the 1st born so he would be less reliant on me for amusement?)
It was a bit mad to have a 2nd child when I wasnt doing too well with the 1st one, but we were too tired to be rational about the decision & luckily (somehow) it worked out fine.
We even had a 3rd child soon after the 2nd! (Then we stopped at 3.)
Now, when I look back at those busy, sleepless yrs, I think the 1st year was definitely the worst. (Such a change from being a free agent.)
So, acknowledge that it's v hard for you at the moment, that your child is not an easy child, (like some others are), & that your feelings are normal/valid.
It will hopefully get better soon. And one day, you will look back and be proud that you managed to struggle through it!
HTH