Been trying for 3 months

With my first I got pregnant the first month we tried with no problems. After he was born I got mirena put in and a year later got pregnant and miscarried while it was still in. It's been out for about 6 months now and we've been trying for 3 months since the doctor gave us the ok and still no luck. I started tracking my period and fertile window but is there anything else I could do to help? Is it still too early to get pregnant after all this? I know 3 months isn't that long but I'm worried