Hello!
I'm not diagnosed either BUT I started off with normal numbers (my grandma monitored my BG as she is diabetic) and started feeling very very strange after eating carbs/sugar a while ago. Now I see numbers up to 19. But I started out with fasting number of 4.2! My diabetic friend said he started out with reactive hypos and feeling unwell after meals before his diagnosis too. It could be your BG shooting high immediately after food though and/or a crash into lows following the meal.
So you see, things can change! And feeling odd after meals is a warning sign that something isn't right, high or low or whatever it may be.
It could be postprandial hypotension or another problem but it's worth getting checked out.
I can't because I'm too young to be tested (I've actually privately requested test from a lab myself after GP refused...) but you are at an age that is considered at risk and should definitely go get some tests done. Catch anything NOW before it gets worse
And I know it's a crummy feeling. Half way through a bar of chocolate and it feels like someone slipped you some pills @_@
Good luck, GET CHECKED OUT OK <3 XXXXXX