I am not going into details, but I know how you feel. My bub had colic so bad that we took her to hospital for the reflux test, because NOTHING was helping!! It put alot of stress on DH and me, because it was our first and I did not know anything. I was crying constantly, thinking I was doing something wrong. I also did not feel like going out, because it was embarresing to go out and your dd is screaming the whole time!!
I also know how you feel about letting someone els look after the bub. I had her, I was the one who must look after her. She is my responsibility. I felt stupid about letting her stay at my mom's.
She is now almost 7 months and has changed completely She is a happy baby. I hated my pead for say this, but it's true: This to shall pass.
Just hold on, and if it gets to you, take it out on us!!!!
(HUGS)