My almost 7 month boy was sleeping pretty well in the night until a couple of weeks back. (Feed around 8plus, sleeps from 9 to sometimes 2-3 ish, at times 5am for feed) He has been waking up crying, 2-3 times each night. His bottom two teeth are out. Any idea what else could it be? He has been sleeping in his room since he was 4 months old and we have a baby monitor.

Hi, It may be because he is teething and may be having some irritation in his gums. Or may be he is in the phase where he is about changing his sleeping pattern as he growing up. The sleeping pattern that he may be having in 3 months, he will not have at one. So, this may be his developmental milestone. Just be patient and pat him back to sleep as you must be doing, and see how he behaves over the period of time. I am sure he will settle down soon. But you must see his paediatrician to make sure that there isn't any colic or tooth related pain that is waking him up.