help to ovulate?

I'm currently ttc. I have irregular periods and ovulation. I seem to ovulate for 2-3 months then skip a month weirdly. Is there any medication I can get to regulate periods and ovulation? I have a BMI of 36 or 37 and currently trying to get it down so please no lecturing on my weight and how losing it can help ( when I started to lose weight that's when my cycles and ovulation actually started to become irregular strangely enough) what medication is out there for us plus size girls? I know I'm over weight but I've seen girls x2 my size having healthy pregnancy. I'm strongly debating on getting clomid online if anyone knows a website to purchase? I'm in the U.K.