I'm in my early 20s, have had my period for ten years now.
When I was younger, it was very heavy (and fairly irregular - as I assume many teens' periods are), so I went on the pill as a result. But never had any significant symptoms: no cramping, no nausea, no back aches or headaches, no significant mood changes etc.
This all leveled out as I got to my late teens and up until now. 30 day cycle, typically, but on the pill anyway. Fairly light, 5-ish days typically and no symptoms at all.
But between last month and this month it seems something has changed. I got my period yesterday and could not sleep last night. Had a sore back, light abdominal cramps (more irritating than painful), but the most significant thing is the nausea. I felt dizzy and unwell all night, and have felt the same today, feeling particularly cold and shaky etc. I know I'm not sick, and I know it's not food-related. So I can only put it down to being my period.
I know a lot of people say they experience changes after having children etc. but is it typical to have such a significant change from one month to the next? 
Thanks in advance!