Really bad trip on THC crystals?

Basically the other night I was with some mates and one of them had been collecting crystals from weed in his grinder for quite some time and we decided to have a joint of just the mixture and some tobacco, god knows how many varietys had been in the mixture. Im not even 100% sure of what it was we had, anyway things started of pretty normal then about 10 minutes later I starter to really freak out, everything was spinning insanely fast and I could barely move. My heart rate increased and started to really pump fast like I was going to have a panic attack or something.

As ive read in previous posts it felt like I was stuck in my mind and nothing in the real world was making sense to me. I tried to act normal but at the time we were watching a film and now I cant remember a single word from it, the whole thing is a totaly blank and I was concentrating on just trying to stay 'sane' as it seemed. My senses started to act really weird especially touch, I kept stroking the wall apprantly because it felt like it was vibrating. I decided to tell my mates that I was having a bad trip and they suggested to just lay down and try ride it out. I felt a bit better laying down as I was now not having to struggle by trying to keep myself upright but in my mind it felt like i was litrally going mentally insane. I could only keep thinking that this would never end and I was going to be stuck like this forever. I was really scared and paranoid of everything around me but I couldnt do anything as it felt like I was trapped.

Eventually most of it wore off after about 2 hours and I managed to get home and sleep, but today I woke up expecting to feel more in touch with myself but im still feeling pretty hazy and fuzzy. When I look back at the trip it sounds to myself really over the top and I never knew I could do this to myself, but at the time I was experiencing really bad emotions and thoughts that I had never felt before, it really did feel so bad and I just wanted to end it.

I was wondering how long this effect might last, and have I done any damage to myself, and what exactly was it I smoked? Im never ever touching any drug again thats for sure after that experience, and yes I have been smoking weed on and off for about 2/3 years and im now 18 and had only experienced a minor bad trip once but this one was totally different.

Any help or advice will be apprichiated as its a hard subject to talk about to someone who has never experienced this.

-kbee