1st time using ovulation predicter,

Okay ladies, I'm new to using opk's but I seen today on glow that It was my fertile week so I thought to my self why not pass by the store & buy an opk & see if Im ovulating & as you can see in the picture I am. But the thing is I had a miscarriage and had to have a D&C and since then I've been ttc for 5months, but so far no luck ๐Ÿ˜• it makes me feel like there's something wrong because if I'm ovulating & having sex during my fertile week & already been pregnant one time then what's going on??why is it harder to get pregnant now then it did the 1st time?? Any ladies on the same boat??๐Ÿ˜•๐Ÿ˜ณ