Irregular periods are my life and I have had problems with them since I was 19. I'm 40 now & have had more years of irregular cycles than regular ones.
Go see a doctor, but don't be surprised if they don't provide much help. I've seen many doctors over the years including an endocrinologist. Pretty much they have offered me the pill. Now that I'm 40 and single, I don't want to be on the pill.
When I was in my 30's and my highest weight, I stopped having my period for 9 months.

The endocrinologist didn't seem the least bit concerned and insisted I didn't have PCOS, even though I had cystic ovaries.
So, I do what other ppl do with PCOS. I diet and exercise, but don't take the PCOS meds. And it worked. I lost 20 pounds and finally got regular again.
But, I have recently lost 20 more pounds and my period is irregular again. My hope is that the hormones will right themselves again. But I need a thorough workup with a gyno ASAP. I want to make sure I'm ok.
Now that I am 40 and periomenopause is around the corner, I like my periods and was disappointed when it didn't come this month. Funny how they call it the curse, for me it has always been a blessing - a sign that my hormones were balanced.