Baby will not let me sleep...

I’m going crazy.... I don’t know what to do. I am exhausted 😩 My 3mo will only sleep if he is on the boob. He doesn’t like the side laying position to eat and fall asleep. He won’t sleep on me anymore because he’s too big. When I finally get him asleep I will lie him right next to me and he will wake right up and start fussing for the boob again. I have to do this a few times until he finally stays asleep. By the time I get to sleep he is awake within 45 min. 😔 the most sleep I get at one point is about 1.5 hours if I am lucky... On occasion he will give me 3hrs at the begging of the night, but then make up for it by waking up every 45 min after that... I’m sooooo tired. What can I do to make this better???? Is there anything that will get me more sleep?