Feel lied about the fourth trimester

Everyone around me said the fourth trimester will be rough then things will get easier but LO is 3 months now and I see no light at the end of the tunnel. She still has reflux, won't sleep in her own crib, wakes up every 30 minutes all night, cries every time she's breastfeeding, is constantly overtired because she won't nap for longer than 20 minutes, fights going to sleep no matter how much we adjust bed time and wake windows, and is still such a fussy and angry baby. I can't even figure out a proper routine with her. I feel like I'm failing her and failing as a mom. Feels like things are just getting worse and I'm physically exhausted and my body aches everywhere. Husband is exhausted too and we're just feeding off of each other's negativity and pessimism about the situation. Feels like it will never get better.