New to ttc

my husband and I are are 27 and we are trying for baby number 3. with the first baby, I got pregnant within 2 weeks of missing 1 depo shot. with the 2nd baby, I got pregnant within 3 weeks of having my mirena removed. My mirena fell out on 12/29/16 and we have not been doing anything to stop me getting pregnant but it has not happened. I thought I had a miscarriage back in march, but it happened again in Sept and I was given a diagnosis of dysmenorrhea. it's not supposed to make it more difficult to get pregnant tho. I have a history of hpv and abnormal paps. I had precancerous dysplasia cells on my cervix when I was 17, but it resolved itself and I have not had an abnormal pap since I had my youngest. My girls are 8 and 5. just, opinion wise, do you ladies think something could be wrong? Or have I just gotten older and my body is having a harder time conceiving? And what are some natural tips for getting pregnant?