are the chances of pregnancy high?

me and my husband have been trying for the last 4 months to conceive another baby with no luck...i had my period on 03/11/11 and ended 03/15/11 which is very normal we had sex like 4 times on 20th of march and no sex on the 21st and again had sex on the 22nd..now on the 23rd i started to cramp lightly and get sore breast and sore nipples and now its march 26 and my cramping is off and on but my breast are still very full and sore i never get this after my period and dont want to be disappointed but is this due to ovulation or possible me being pregnant????