When do I ovulate if...?

well, birth control is no good if you want a baby. Since your periods are less than 21 days I'd go to your doctor for advice as that isn't normal.

Keep having the regular sex, but also you could get a urine based ovulation test (can get cheap on amazon) as a chart won't work if your cycle isn't 'normal'. You test between noon and evening using strong urine so stop drinking 2 hrs before you test and leave them the full 10 mins as I found a faint positive the day before appeared late in the waiting time. The test line was never as dark as the control, but a clear line present.

http://www.amazon.co.uk/Highly-Sensitive-Ovulation...

Well, in July you had a 21-day cycle, which is short, but still in the "normal" range for healthy females. And of course a 21-day cycle means you're going to consistently get two periods a month, since every month on the calendar is at least a week longer than your cycle.

It also means you might be ovulating earlier than most.

But bleeding again 9-10 days into your next cycle, which is what's happening now, is a sign that your hormones are off. And if your hormones aren't just right, you might not be ovulating at all. If this happens a LOT, not just occasionally, you might have a tough time getting pregnant on your own.

Sometimes going on birth control for a few months shocks your reproductive system into good behavior for a while. This is something you might want to discuss with your doctor.

You might also want to start temperature-charting, which will give you a good idea of when and if you're ovulating. It's drug-free and only costs a few dollars, for a basal-body thermometer and some paper to write your numbers down every day.

try using a period tracker or an ovulation tracker it may help