Im really late!!

My period has been acting really weird lately. It started about a month before we started testing in school. My period was here in April, it was late may but i spotted a little bit. I had one in June, and i remember because it was on during my senior trip and I got up a few times during the movie 😂😂😂 its due on the 15th of this month and my birthday is the 20th!!!!!!! What can i do to keep it going regular like before?