I am so sorry for your losses. I too have had a miscarriage. This was in between my son and my daughter, and I conceived my daughter about 3 months after the m/c, so it most definitely is possible.
I really would talk to you doctor about the recurrent m/c's. 3 consecutively seems like there would be an underlining issue to tackle or address before ttc again.
I would also recommend checking out the website FertilityFriend. It is a great site!! That is where I learned to chart my cycle and understand it a little better. The book, Taking Charge of Your Fertility is also a great little "assistant" to have when ttc.
There really isn't an exact timeframe for when you are fertile and ready for that little baby dancing to take place. It is sooo different from woman to woman so learning the signs of your body is the BEST way to make a more "educated guess" for when that egg is on the move.
The website has chat rooms and tons of people to talk to about charting and all of that. It was great!
D.