My 4 month old has never been a great sleeper, in the hospital I expressed concern several times that he was not sleeping. When we got home he slept for 15-30 minute stretches due to poor latching (tongue-tie) until I started exclusively pumping. We started swaddling/white noise/bed time routine as well and he went to doing a 3 hour stretch in the early evening and then waking every 1.5-2 hours or so until the morning. At 3 months old he stopped doing the 3 hour stretch. Now at 4 months old, he'll do a 1.5-2 hour stretch and then he's up every 30-45 minutes until morning. His naps used to be okay but now he's completely regressed on those as well - doing only 2-3 naps the entire day for a total of 3-3.5 hours. Altogether he's not getting more than 9-10 hours max of sleep in a 24-hour period.
We suspected silent reflux so we got him a rock n play (he's never spit up), he sleeps in that and it doesn't make a difference. We've tried co-sleeping. We've tried the Mamaroo. We tried swaddling/not swaddling and do white noise. We've tried modified CIO (going in every 5 minutes). The only thing that gets him to sleep (or back to sleep) is milk. The past month though he only drinks when in the rock n play or in his car seat, he won't drink in my arms. He was 7 lbs 5 oz at birth and now he's 17+ lbs. At his peak he was drinking close to 45 oz of milk per day, but he's since tapered off to about 32 oz. Our pediatrician dismissed his sleeping patterns and told us he was at risk for being overweight (which sounds crazy to me because he only drinks breastmilk). People do regularly think he's around 8 months though. I'm at my wits end, I don't know why my son won't sleep. I can see he's tired and I know he needs a solid block of sleep. Has anyone else experienced this? Could it be allergies (he's got a bit of eczema on his eyebrows/forehead, I keep it at bay with Aveeno lotion)? I don't drink cow's milk and I don't eat anything soy/nut related because I'm allergic. All advice appreciated.
edit: just wanted to add, his tongue tie was fixed. and he was a very quick all-natural birth, we've been to a chiro to fix any alignment issues and it didn't help at all.