Help!!

So I’ll be 18 this year and got my first period when I was 14. Well ever since I have been extremely irregular and I’m starting to think it isn’t normal. Keep in mind I hardly ever go to the doctor and have never been to a gyno and I’m a virgin... well my first year I only had 2 periods, the second I had 5, the third I only had 2, and I haven’t had one in 2018 yet. Other than the last 2 I had my periods are usually extremely painful and very heavy. I was just hoping someone could give some perspective on what this could be or if I should be worried or if I’m just being obnoxious.

Thank you so much!