Don't think I'm ovulating?

 So I've been Diligently TTC for about 6 months now. I've read up on everything & am tracking everything, and I'm not noticing any of the signs of ovulation each month. I even bought an ovulation test kit this past mont and never got good readings off  of them. My periods are very heavy but regular. And no changes in discharge or any other hormonal triggers. I am under a lot of stress and haven't been the healthiest in the past couple of years. I've gained a lot of weight, but have been cleaning up my lifestyle in the last few months. Is not ovulating a common thing, and what causes it? What can help fix it?