Doubting my mother skills

My LO is being really fussy the past few days and her cries just stress me out, I'm crying with her because I don't know how to make it right! I keep it together in front of others but I'm pretty much going through the motions, it feels lonely despite having others help you. The crying drains me and I have no motivation to work on my body. I'm getting bitter at people trying to touch my baby and having to hear critisism. How are you coping as a new mom?