so I'm on cycle 7

Hannah
After what looked like a promising calendar last cycle and a possible BFP, AF arrived 3 days early. I'm okay with it just moving onto another cycle. My question is.... 
If you're having periods am I ovulating every month? I got a positive opk last month I've read somewhere you only get  regular AF after O- is this true? 
Or can you still get AF every 28-30 days (for me) even without O?