Habitual 5.30am awake

Has anyone experienced this as found a way to break it? I have tried all the usual dark room, feed more before bed, temperature changes, later bedtime, earlier bedtime and he will still wake anywhere between 5.15-5.45am each day really upset - I can see he needs more sleep but is just unable to get himself back to sleep. It has been going on for 4 months now and I am So tired! Help/advice needed please!!!