Flatmate spiked my drink

I've never really got on with my flatmate in halls- she's really rude, loud and messy. She's never taken our feelings into consideration when she brings back parties at 3am on worknights, and i had fallen out with her a few times because of this.
When i turned 18 not so long ago she asked if i wanted to join her and her friends on a night out, so i said yes cause it would be my first club, and it was great. So i started to become friends with her and her friends, and trusted them as i'd gone out with them a few times since.

The last time i went out with them we pre-drank at our flat. I NEVER get drunk on smirnoff, ever. I only had two small drinks mixed with lemonade. I was telling one of the guys there about a CD so went to my room for literally 20 seconds to get it, leaving my drink on my kitchen table with people i'd become friends with a few weeks ago, and my flatmate there. It never even crossed my mind not to trust them as they were lovely people (apart from my flatmate anyway..) So came back and one of the guys watched me drink but i didn't think anything of it. Then i felt very drunk, not a normal kind of drunk though, more drugged. I couldn't stop laughing, uncontrollably at absolutely nothing. I was really embarrassing myself and couldn't control my actions at all. I'm a bit hazy but i remember talking nonsense and drawing cockroaches on sticky notes and tearing the leaves off of a pineapple.... this really isn't normal for me, and i did not drink nearly enough to be drunk. I went out leaving the others and just went with 1 guy to a club, but they wouldn't let me in. I ended up back in the flat at 1am, the others were all out and this guy fell asleep on my bed, i was exhausted and fell asleep too.

When my flatmate came home drunk she burst out laughing thinking i had sex with this guy, and i honestly didn't. i know i was in a bad way but i was way better and none of my clothes were off, i know for a fact i did not sleep with him, + i like girls but she doesn't know that.

The next morning i only started to wonder if they had put something in my drink, as i'd seen them with legal highs and weed before. I'm sure i remember seeing pills at the start of the night but no one took any in front of me and i trusted them. Does this sound like ecstasy? I've only smoked before, never taken any pills or done serious drugs, and never would. I'm really upset about this. It sounds like ecstasy from what i've heard. Did my friends risk my life for a joke, or this could have been my flatmate getting revenge for me asking her to keep the noise down at 5am? :/

Wow she sounds a nasty piece of work what she did is totally out of order

They probably just poured a little extra vodka in your drink and you got drunk so not too much of a big deal, people do this to mates all the time. I mean last year we always poured a little vodka to a girl in our flats smirnoff ices just so she would relax and be less of a downer..
Just act all happy with them, maybe trick them somehow, and get them to admit to it?

I've never done that to a friend and never would. That's actually a really horrible thing to do. You're effectively taking control of what someone's putting in their body out of their hands and tricking them into drinking what could be an unhealthy or dangerous amount of alcohol. It's morally equivalent to spiking with a drug. How can you think that that's 'not a big deal'?