Firstly, so sorry to hear of your loss.
I think most Dr's would tell you to wait until you have had at least 3 normal periods before TTC. That way you are giving your body (womb especially) time to fully heal. I miscarried at 13 weeks and was devastated and could not wait to start trying again but I listened to my Dr's advice, waited the three months and now have a beautiful little girl.
I think if you dont give yourself time to physically and emotionally heal, you have a higher chance of miscarriage. I also think too that it depends on how far along you were with your pregnancy when you m/c. The further along, the more time you should wait. Good luck with everything.