Hi there ~ What you describe to me is a typical circadian rhythm (day night time table) sleep problem. It is quite possible that you feel sleepy after meals as is normally the case. However sleeping late like in your case and waking up early may result in less hours of total sleep time which may result in daytime sleepiness
. It is also quite possible that you may be able to undo this by sleeping early and waking up at the same time. You would just need to put behind all those things you were doing closer to bedtime to an earlier time and start winding down early to go to bed. If this, and relaxation while trying to sleep are still not helping, you may need to consult a doctor. I hope this helped. Take care.