Ovulation help. PLEASE. I've never taken ovulation tests before

Caitlin
Hey guys!  So this might be a lot. But I am confused lol. 
We have gotten pregnant 3 times and have miscarried each time. So we really want a baby like NOW. lol. 
My cycles have always been regular. ALWAYS!  28 day cycle. 
I had an ovarian cyst removed in November. And between the weird period I had after it (2 1/2 days long...usually always 5 days). 
I had a 34 day cycle. I have never done ovulation tests before this month, and now I am on cycle day 15. The second line is light. When should I be ovulating with a cycle that long?  My husband travels for work so I want to make sure he is home in time to have sex on my peak day
I first took an ovulation test on Cycle day 13 and there was barely a second line 
Cycle day 14 it was there but not too noticeable. 
And then today it was darker  
Is that how those things work??