Male high singing problem

Hi guys..I'm a male 21 yrs old and have a problem singing high notes...I started singing when I was 18 and so it's been about 3 years.When I first started singing I couldn't even hit A3 and now through youtube and some research I can hit upto C#5 and even D5 sometimes.It's not head voice because I have no idea how to do it and not falsetto because it's loud and heavy.Also my falsetto is pretty weak.And hitting those high notes does not hurt but I can't get used to singing on those notes.I feel weak sometimes and can't use it more efficently.I can easily upto E4 and above that I just use diaphram support which has just been 8 months since I figured out to use it.
So my question is will I be able to sing those high notes properly or am I just pushing it ?
And I've no idea if I am a baritone or not...
Sorry for the long part.I just wanted to make it clear..
I can't go low as what I used to when I started.Before power D2 - now weak and breathy E2 almost feel like puking sometimes.
And sorry again I used to take classes but not now because where I live no one teaches how to go high...So guys ??