Hi PartySarah,
So, we recommend people refrain from having sex after taking EC for at least a few days, just for their own peace of mind. You can read more about why we recommend that towards the bottom of this article:
Emergency Contraception (Plan B or the Morning-After-Pill). Too, just to check, have you been talking with your partners about STI status? And are you getting tested regularly?
As far as forgetting condoms goes, what if you had a little safer sex kit that you always kept stocked? You could even make it small enough to be portable if you were going out. And, if you're planning on being sexually active for the foreseeable future, it might also be time to think about whether you'd like to get on a more consistent birth control method, like the pill or the IUD.