Missed pill day after having sex

I study in a different city than my hometown and yesterday while packing I forgot my pills. I had sex on the same night (yesterday) with my boyfriend and only found out right now that I left my pills at home. I did take a pill the same day I had sex, so how at risk am I?

My boyfriend’s currently out to buy me a new package, but it’s night here and he probably won’t be able to find it. In that case I’m going myself first thing tomorrow. Also I’m on the combination pill, on the sixth day of the first week after break and yesterday I took it at about 5:30 pm (it’s 9 pm now)