Why is motherhood feeling like a hard hood?

I am 10weeks pp and I feel sad most times. I love my baby yes, but I feel like am taking care of him alone since my partner is always busy with something and when he’s home, the baby will still want my attention. So am feeling like am loosing myself and it’s getting so heavy from inside that sometimes I feel like I could use some time alone. But don’t get me wrong, I’d do anything for my baby boy, it’s just that it’s really getting harder by the day and when he cries and I don’t know what’s wrong with him I feel like am being a bad mom too😭💔