Brw Discharge, no period, pills, implantation? Deployed fiance!

OK..first off..I know there is only one sure way to know for sure and i have an appointment on Tuesday which is the same day that my fiance is being deployed so i need to give him some heads up b4 he come back ...also took a home test which came out negative..but we know how that goes...
Ok i'm on Birth Control and we had sex on New year's (whoohoo) and i missed that day's pill and doubled up the next day(so i missed Sunday,the start of a new pack, and took it monday 1st & 2nd)
My menstrual was suppose to come on the 25th but instead i got only a brown discharge on the 24th with a few light spot of pink .,,only lasted for 3days
Had heartburn,gas,cramps, and headaches the 23th the 27th..could it be IMPLANTATION? Bc it's 2-3weeks after sex and around the same time of period
I have been on the pill b4 and never experiences this b4 and i have return to this method for 4mnt now. I know it is normal to see old blood after your menstrual but b4 not so sure..
NO symptoms and i don't know if im not pregnant or i took the test too early...so im getting blood done..BUT MY FIANCE IS LEAVING TUESDAY..and i don't know if i should tell him now bc we wont be able to talk or write til may..?

thanks in advance..