Aww don't beat yourself up about it 
I used to be a right harlot back in the day (I am now 26 with a 3 week old baby so have aged overnight) and I remember the feeling of shame the day after ye olde uno night stand too!
If it makes you feel any better about your predicament here is a sorry tale of mine to cheer you up.
I went home with a guy who looked like Vin Diesel (had massive Vin crush at the time lol), usual scenario, met guy in club, got totally pissed and went back to his like the classy bird I am. Anyway, DTD and it was shite like most one nighters.
Next morning (early, like 6am early) I wake up in horror wondering why the hell I am in stinky man bed and want to just, well die. I fling my clothes on (last nights outfit) and wake up Vin (looks less like Vin in the morning) and tell him to let me out. As we are creeping across the landing, his entire family proceed to congregate at the banisters in pyjamas and dressing gowns (mum, dad, Dsis, Dbro, cat, dog, fucking hamster) and ask "who are you? Where is Carla? Are you cheating on Carla?"
I leg it the fuck out of that house, cheeky twat didn't tell me he had a GF!! And his entire family saw me and must have assumed I knew like some....Scarlett woman!!
To top it all off I look in my bag to find my funds are drastically depleted and have to phone my mum to come and rescue me, highlighting the fact I hadn't stayed at my cousins house after all.
Don't worry OP, just put it down to experience and move on. Also get STI screened to be on safe side, for your little bambino.
Chin up xxxx