when i was trying to get pregnant with my son it was very hard cause my period were iiregular too but i had my last period November 22nd 2008 and then on Dec 3rd 2008 was the day i concevied the doctor told me. so i guess you can get pergnant shortly after. Good luck and i hope that helped you. Baby dust.
I actually take Provera to start my periods that way I know when I am ovulating. I actually have to take clomid. But My ovulation is my doctor told me just to have sex from day 10 after the period to day 20.... Which if you get on the pregnancy calenders some of them if you put the beginning of your period date and calculate it will tell you when you should be ovulating. I would also look for signs of ovulation that way you can learn your body. Temperature also. If your temperature is above normal after taking it for days that means you've ovulated so hopefully you had intercoarse then>>> LOL hope it work.s