Well, the only good way to test for herpes is to take a swab from an active outbreak. There is a blood test, but it isn't as specific or as accurate as an active swab. Does your boyfriend know for SURE that the STD panel they did recently included a herpes test? They often don't, unless you specifically ask. Therefore, he could have been clean from the things they did test for (like chlamydia and syphilis), but they might not have tested for herpes. And the joy of herpes is that it can spread without visible lesions--you can shed virus before the sores appear, and you might get an almost breakout that never got to the visible lesions stage. I would think that a nurse who works in ob/gyn a lot would know what herpes looks like, although I'm sure they can make mistakes, as they're only human. You'll know your own results soon enough.
You can get genital herpes in your mouth (or oral herpes on your genitals) from oral sex, but it's not 100% going to happen every time, so you not getting cold sores doesn't mean you didn't get genital herpes. UTIs don't cause blisters, although they can cause urgency and burning with urination. Eating things with yeast in them isn't what gives you a yeast infection. You always have some yeast in your vagina, and this is normal and healthy. Sometimes, something causes the yeast to overgrow, at which point it becomes a problem. Having sex sometimes does this, and using lube with sugar in it (like flavored lube) is a great way to do it, since you're giving the yeast a direct source of food (eating sugar isn't a problem when it comes to yeast infections).
I hate to say it, but your boyfriend could have gotten herpes in between when he was last tested and when you had sex. Are you sure he hasn't had an outbreak of something after he went back home? Or, if they didn't really test him for herpes, or they did but it was a false negative, he could have had an almost outbreak. If you had a cold, that might have made it easier for you to catch it (later herpes outbreaks happen when you're immune system is weakened, which is why ones on the mouth are called cold sores--they happen when you get sick).
Taking your friend's birth control and that much ibuprofen like that is a really bad idea. Don't do it. If you want to be able to skip periods, get a monophasic (all pills same dose) birth control pill for yourself, and just start a new pack after week 3 anytime you want to skip a period (but you shouldn't do it more than 3 months in a row). Ibuprofen can give you stomach ulcers in overdose, and is bad for your kidneys. I also don't know of any mechanism by which it would stop a period. And too many birth control pills at once can act like a morning after pill, which can cause lots of cramps and bleeding. It's a bad idea to screw around with prescription drugs like that on the advice of the internet (or anyone not a healthcare provider).