So I got back with Sam :)
This time though we're taking a totally different approach. We're spending more time apart so when we do get time together, its more quality than quantity.
We're learning to trust again, and tonight I'm at my mums house while he's out, and I'm trusting him to not take anything (drugs wise) and to not stay out all night. He's trusting me by believing that I'm staying in my mums house, and not going out to meet other people to get off it.
I'm really happy! It seems like a big weight has been lifted off my shoulders and me and Sam are having fun again, like when we first got together.
I think you'll all be happy to know I'm off MCAT, haven't had it or wanted it for four weeks now. I must admit I did a couple of weekend binges on speed, but that drug is definitely NOT for me as it made me hallucinate and made me feel really bad.. So there is no worries there.
I feel like I'm finally getting my life back.