Period being weird?

Demi

So I took my period on the 10th of January it’s was quite light no cramps which I usually suffer bad with and it only lasted till the 13th but my period is usually 6 days. I woke up yesterday the 30th of January with really bad cramps and was really confused until I went to the toilet and there was period blood in it. The past year it’s went between coming on the first and then switching to the 10th, so basically it’s been im late until the 10th or it’s early on the 1st. On march last year I had my period on the 16th and then didn’t get it until the 30th of April so basically skipped a whole month of one. I’ve never had a 4 day period followed up by one at the end of the month so I’m really confused right now and was wondering if anyone knows what’s happening? I’m 20 btw so they should be pretty regular right now and my doctors won’t listen to me anytime i ask them about it.