i don't know if i should do morning or afternoon...im a morning person like most days I'm awake at 5:30, some days even 4ish, and my sleep in is 6:30. so i could do the morning one...but I'm kinda worried that i might feel dead that morning and not feel like doing it so early.
the problem with the afternoon one is that, knowing me...ill get up that day and do umat study. and even if i force myself not to do intensive study, i will still do some study. Because of that I'm kinda worried that by the time the actual test starts ill be mentally tired
idk what to do 
any advice would be appreciated (please)
If I was you, I would go afternoon. The thing is, the decision to not study is easier then trying to keep yourself awake and mentally alert for the umat in the morning. Hence, logically, it is safer to go with the afternoon. If you have trouble with that, sit down and watch a movie or meet up with some friends before the umat.
Point is,
In one scenario, you can't control your ability to stay awak
In the other scenario, you struggle with not worrying about the umat and hence you study,
IMO, the second one seems easier to get around.