Baby won’t sleep

I need sleep. I’ve tried everything. I have taking Cara babies. Room is dark. Sound machine. Everything. But my 4 month old still sleeps like a newborn baby!!!!!! He’s up every 90 minutes and I’m dying over here. I haven’t slept through the night in like 6 months and I thought by now he would be over this phase. I obviously know I can’t let him just cry it out but what can I do? I’m f*cking exhausted and it’s affecting my daily life. HELP