What Causes Abdominal Cramps, Fatigue And Brown Spotting Before Menstruation?

hi there! my hubby and i are ttc..for 4 mos my regular period was on a 29-30 cycle..then on my last period i just had 26...and prior to my period i actually felt symptoms of what i thought were pregnancy symptoms..nausea in the morning and night, abdominal cramps, food cravings, fatique and some light reddish brown spotting..so i got really confused but eventually i had my period...i wonder what were those things i experienced...?

also when would be the best days for my hubby and i to have contact..?my last period was oct 30 until nov1...