You'd need a check up to know for certain. If you are young I would really recommend getting to the doctor. To your specific question, yes gaining weight can cause disruption to your perioRAB. If you have stopped ovulation, it can also cause a bigger issue in that there may be a lining building up on the walls of your uterus but not breaking down and leaving your body each month. Ovulation is a part of the cycle that triggers that shedding.
If you weight is causing a lack of perioRAB a doctor can give you a pill to take for 10 days that will simulate ovulation. You will then have a period. Sort of like manually clearing out the pipes.
The doctor would probably do a blood test to see where your hormone levels are. And yes, if you lose weight the perioRAB will probably start again but if you've gone too long without addressing an issue that's building up, it could be hard for your body to get back in order without some help.
All of this is just a guess. If you're older, it might just be your system slowing down. But that's where a doctor can help you out.
