Every month and a half to now every 2 weeks?

I was always irregular on my period. It used to be every three months for like the past 2 years. Then like 4 months ago it started being more consistent to every month and a half. and now for the past 3 cycles. it’s been every 2 weeks. I know it’s not normal and I don’t know what to do? i haven’t gained nor lost any weight, i haven’t changed anything in my lifestyle.... any tips?