Anxiety causing lack of sleep...lack of sleep causing anxiety. Help?

I'm currently in this circle where I'm struggling to sleep because I'm anxious yet the more tired I'm getting, the more anxious I'm getting.

My stomach got bad last summer, and after doctors ran tests, they came back clear and he diagnosed me with anxiety. I was on tablets for it that did seem to help, and generally towards January/February this year was when I started to feel better.
It was around the end of May this year that I started to feel it coming back. I was being messed around by some girl I liked, as well as having exams approaching so I did go back on the medication for a few weeks.

But it all started Mid-June really. I'd been talking to some girl on Facebook for a few weeks and we'd started to like each other and admitted it. We met up for the first time and we really got along and liked each other all the more, and arranged to meet again two days later. But it was the night before meeting her for the second time that I didn't sleep very well. I had my theory test the next day and also some college thing I was stuck with that I had to finish off, as well as then meeting her and nervous, so I could totally understand not sleeping that night. But we did meet, everything went fine and we also made the relationship official.

But I'm quite insecure really in myself. I thought the relationship was a bit of a joke at first and so I couldn't understand what she saw in me at all, but two months onwards and we're still together. Yet I'm still not sleeping.

On top of the relationship worries, I was also stressing over where I'm going to be next month in terms of university or a job. This is because I wasn't expecting the grades to get into university because I never passed maths and English in school and had to re-sit within college. I wasn't expecting the grades, but also didn't have a clue where I was going to end up or what to do either, so that was stressing me out. But I got my results on Thursday and they're really quite high, guaranteeing my university place at my first choice university. But as soon as I got the grades and got my place, it never hit me. It still hasn't. I was that convinced I'd failed, none of this seems real at all and it's putting me on edge really. But it still hasn't sunk in really.

And finally there was something else that hit me last week. I came across a baby photo of me being held by my grandma who still to this day I'm really close with. But sat next to her was my grandma from my dad's side who died when I was around age three, but things are more complicated in that that I won't go into details of, but basically it kind of really just hit me seeing her. I had to ask my mum if that was my grandma, and I didn't even know her name.

But all this is kind of going around in my head and I'm not sleeping. I'm no longer on the medication for my anxiety but even if I do take them, they don't really do anything for me. But the more tired I'm also getting from the lack of sleep, the more anxious I'm getting. I'm just falling asleep but then waking up every hour. Sometimes in a panic and others just generally waking up. All weekend I've pretty much been in a state because I've been so tired.

I've booked an appointment with the doctor for Wednesday but generally I don't want to be on sleeping tablets or any general anxiety medication. But I am forever worrying about my relationship, my future and other general things really and I just want to be calm and happy.

Any help? Advice? Stories?