I never thought I'd hate shopping...

Yesterday started off as a good day. I'm on earlies this week, so getting up at 4.30am wasn't a great start, but going through he day I found myself in a fab mood, and not even that tired. So after work, I decided to go into town to look for some new jeans. Unfortunately the ones I've been wearing have been worn to death, and now there's some noticable wear-tears in the crotch. Have tried stitching it back up which lasted about a week, but now the rips have come back with a vengance. There's no saving them this time... Now usually I quite like shopping, yeah, strange - a girl liking shopping, but after yesterdays traumatising experience I fucking hate it. My main beef is with womens sizes. You might try on a size 12 in 3 different shops, and each pair could actually be anything from a size 10, to a 14. Now it doesn't help that with my recent weight gain over the past few months, a size 12 which used to fit perfectly, is actually quite snug (and by snug I mean I can't pull it past my thunder-thighs). Add to that the inconsistancy with sizes anyways (and I'm finding jeans are generally a size smaller than all other trousers), then you can start to imagine what a struggle I'm having.
So the first places I tried I was just taking in size 12's, until I realised what I was up against. I daren't go back out to change them for a size bigger, not with all the stick-thin girls standing by the rails, complaining there wasn't anything smaller than a size 10. So I get dressed and move on. The next place I go I take in 2 styles of jeans, both in a 12 and a 14 (now at this point I'm already getting quite down as I've never been a 14 in my life, and am now faced with the reality that I really have put on that much weight. This is not good). I tried the 14's, and my mood fell when I realised even these wouldn't get past my thighs. Well there was no point in trying the 12's. So I tried the other style - well they may be cut differently or something... but no, they only managed an inch higher than the first ones, and unless I'm going to become a bloke and wear my jeans round my crotch, then they were no good. I was mortified. There was no way I was going to ask the pretty girl standing outside to change them for a 16. That's not even an option. So I stand there, looking shamefully at the girl in the mirror. Trying desperately hard to hold back the tears welling up in my eyes. I couldn't stay there any longer. Yet again I pulled my clothes back on, and must've thrown the jeans back at the fitting-room assistant and almost ran out the shop. When I got on the bus back home I was still holding back tears. Tears of humiliation, tears of sadness, and tears of frustration. I couldn't believe what I'd become. By the time my bus pulled up on my street, the rain had started.
Now normally the first sign of rain and my pink monkey brolly comes out. Not this time. I just didn't care. So after walking down the road and up to my door, I was soaking.
I thought I did quite well though, in the 4hrs I was home waiting for J to come back from work, I didn't cry. I'd put it out my mind and had vowed to do a better job of loosing weight. Then J came home and asked me if I'd got any jeans. Five minutes later we were sat on the sofa, my crying my heart out on his shoulder. I felt really pathetic and stupid getting so upset over something that shouldn't matter. I was also feeling guilty for unloading so much onto J who had only just got back from work, and the last thing he would've wanted is an emotional girlfriend crying all over him. Thankfully he was being the perfect boyfriend about it all - telling me not to apologise, and that's what boyf's are for. I still felt guilty about it. He'd not even got changed yet.
So now I'm really wanting to do something about my weight. I've tried cutting down eating crap, but I have no self-dicirpline (not that it helps that naughty food is so much more tasty than no-fat, no-calorie, no-sugar stuff), I've tried diet-type tablets, but they don't work, and I've tried excercise vids, but they make me depressed. I can't go to a gym cos I'm too embarrassed and I can't afford it, and although I love swimming, I'm too embarrased to squeeze into a swimsuit. So what do I do?! I've looked on so many websites and all the info I've read is so contradictory to how best to lose weight and what excercises to do and for how long, I don't even know where to start. All I know is I'm going to have to do something soon, before I put on any more weight, or fall into a self-loathing depression all over again...