getting frustrated

so I've just started using this tracking app this month to start trying to pin point down when to boost up our baby making activities... first week ever using ovulation testing...day 3 since my ovulation week turned green and still no surge...getting discouraged and frustrated... and worried that I'm not going to ovulate at all. was told by 2 doctors when I was in my 20s that I couldn't get pregnant without fertility treatments. so I came to terms a long time ago I may never be a mom. until I had a surprise pregnancy 2 years ago. sadly I miscarried at 11 weeks. and my OGYN at that time said I shouldn't have any trouble having a baby. hubby and I have stopped birth control and been off of it for 3 almost 4 months and still no luck. starting to wonder if miscarriage baby was a fluke.