Neep help. Lots of questions.

2. I was on the implant birth control (that they put into your arm) for almost 3 years. So now my period is very irregular, because I have only been off of it about a month. I had my period end of September, I felt like I was ovulating because I could feel it on my right side. Was off of my period about a week and started again. So am I ovulating again after my period ends this week? And how can you tell you are ovulating without buying tons of expensive ovulation test? HELP.