Period twice in one month.

Nina
OK so I stopped taking clomid last month and had my period on the first and the second. So I'm thinking that my next one would be next month in August but to my surprise I got up July 28 and I was on my period. Now I never had two period in one month, I was diagnosis with pcos in December 2015. I was really freaked out because I don't think that's normal.