To get pregnant or not to that is the question.

I really would love to have another baby but am afraid because of a few health issues I have even though the doc has given me the ok. Almost a year and a half ago I had a cardiac ablation where they go in and basically zap or burn a small area in my heart that is causing the problem. I had SVT which is a really fast heart rate. I also have thyroid problems and have to take a pill for that everyday. Even though my cardiologist has given me the ok I'm still nervous about it even though I really want to get pregant. I guess I'm just concerned that could my body and heart actually handle a pregnancy. I've prayed about it but truly still don't know if this is something I should go through with even though I really would like to have another child. I know there are other women out there who have more if not worse health issues that me that get pregnant so why the heck am I so nervous about this. I guess too that I know I'm not in the best shape just because I don't work out. I'm not over weight or anything but I know I could be in better shape. My dilema is though is I also have endometreosis and have been told if I want another child I need to do it soon because with the way things look I may not have much longer that I can concieve. So I really don't even have the time to get myself in shape before a pregnancy. It's now or never pretty much. So with all that said....advice please!!!!!!