After the depo it can take up to a year for your cycle and fertility to return to normal (although it's not reliable as contraception during that time).
Normally when you ovulate, you'll have a period around 14 days later (it could be between 10-16 days). So you may not have ovulated yet, or you may have ovulated but you won't find out until your period starts. Once you've had a period it will be easier to start following your monthly cycle again.
In the meantime have you thought of using ovulation predictor kits (OPKs) so that you don't miss the time of ovulation if it happens? And it could help to be aware of the signs of ovulation too.