Work is stressing me out and messing up my periods

I work at a smoke shop and I have a boss that is so rigid that any tiny thing I do is a write up. The company is extremely sexist (and I think racist since there has not been one black worker that I’ve seen at any of the shops). I’ve been under so much pressure to be perfect that my periods have become heavier and even more spread out than they used to be. Now I get them every 2 months or more. I can’t lose this job, is there any way I can regulate my stress and period in spite of this horrid company?