Doing 2 packs in a row?

So my long distance boyfriend is coming over for 3 days in 10 days, and we've talked about sex, I'm not a virgin but he is and we've decided we want to have sex when he comes over. The issue is, my pack of pills ends in 9 days, that will mean my period will start when we were planning to have sex. I'm on rigevidon and the instructions say you can take one pack after the other to prevent period but I may have breakthrough bleeding. Can anyone give me further advice or help with this???