Weak and dizzy... T_T?

As of the past month or so my head has felt heavy or i feel like I have a fever and I seem to be tiered all the time and just want to sleep. I just got back from holiday in Japan on the 1st of june and even while there I had to force myself to go out. I just don’t want to feel sleepy any more! I usually perky and have a smart mouth but I just don’t have the energy. WHAT is wrong?!?!?! i eat bananas and drink water and go to bed at a normal time! im only 24 -_-