Hi I just turned 18 and my period's been acting weird. One day when I wiped I found a little bit of blood then the next day no blood the 3rd day which was yesterday I found a lot of blood so I put a pad and then later that night found nothing and when I woke up I still found nothing, the whole day today there was nothing until this evening there was a lot of blood. I also feel like my blood sugar level is low because every night I feel like eating something sugary or chocolate and I drink a lot of water after. Last time I got my period was January 22.what can that be?

Variations in flow are so common that it is impossible to guess if your 'symptoms' are nothing, or something. Variations in days in cycle can change, no matter how long they were consistent.
Doctors will call this wait-and-see, unless you have known history, or immediate family history.

How is it that you mention your blood sugar level, if you don't have diabetes?
Please don't go online (or to a doctor) for ANYTHING without saying that FIRST!

We can't diagnose online.

Off periods happen to everyone at least once in their life. At 18 you'll have many different periods, until you're older and they settle a bit.

Your doctor knows your history. Your doctor also knows if you're sexually active, at least he/she should know that to give you better service. You mention low blood sugar. How do you know that your blood sugar is low? Wanting to eat more sweets is also something women that are menstruating, or are having PMS, do.

Is pregnancy a possibility? Are you sexually active? If so, is miscarriage a possibility?

It's time to see your doctor, and you have to tell your doctor everything that's going on in order to get the right diagnosis, if there is a diagnosis to give. To me it just sounds like an off period, but no one online can diagnose, not even a doctor.

Good luck.