Well, I like you
There is some stuff in my binge drinking thread that is basically intended to counter anxiety in a party atmosphere, but I wouldn't recommend using these things habitually. Check out the Edot thread, and it might be worth searching 'anxiety' and if that's not fruitful maybe repeat your post there too, because there's a vast range of plant knowledge there so they should be able to come up with a near-exhaustive list of suggestions. Don't forget to tell us over here what you found out too
I know how you feel. However, a true lasting change is I doubt chemically induced. What helped me was exactly as you are doing- putting yourself continually in situations that will teach you not to be shy. Habituating yourself to them. I got a job as a waiter then barman when I was 18, and that helped. I did find that I would revert to type to an extent when no longer working the bar, but only to an extent.
A bit of cognitive behaviour therapy by reading 'Feeling Good: The NEw Mood Therapy' by David D. Burns is I would say essential. Otherwise you'll just keep scuppering yourself with negative thoughts. I think this would be really helpful for you, because thinking that everyone hates you sounds like a damaging delusion to me.
Incidentally, the newer version of that book covers prescription anti-depressants such as the ones you asked about. However, I'm very suspicious of anti-depressants myself and personally wouldn't go down that road unless I had no other options left.
Following on from my previous groundwork, my next goal was to get over shyness enought to live an extraordinary rather than an ordinary life. Jack Kerouac actually inspired me that extra bit- early Jack, before the booze got to him, such as 'On the Road'. When I really want to do something but am anxious about doing so, I just think "What would Jack do?". I think about how I want an extraordinary life, a self-actualised one, with no enticing opportunity missed. I gear myself up with this thought, and do it.
For example, I was on a bus shortly after reading On The Road, and a hot girl got on. There are lots of hot girls where I live, so at that point I wasn't super-interested, but when I saw she had an arty book in her hand I really wanted to talk to her. But it's not the 'done thing' to talk to people on buses where I live (unfriendly place!). So when my stop came, and I'd wussed out and got off, I thought "what the fuck are you doing wasting your life like that?" Here's where I decided to live like Jack. Judging by her book, I thought she probably will be getting off in my area as it's the 'arty' one. So I ran to the next bus stop! Of course I slowed down as I got near so I wouldn't look crazy. She wasn't there. So I ran to the next one! And guess what, she was there, leaning against the wall waiting for her friend. I went up to her and said hello, that I'd seen her on the bus and that I saw that she liked art by her book, and that I thought how stupid it was to not talk to someone just because they're on a bus. I was unbelievably nervous but I managed to pull it together- the running probably helped. She was surprised, but she liked it, and I got her number. We went on a date. Score! Of course, I still let opportunities slip nowadays, but less often and when I REALLY want to do something, I now go for it. A few months ago I actually did chat up a girl on a bus because she was hot and had a guitar (irrisistable combination!), so I guess the practice is paying off... I didn't get round to actually swapping numbers that particular time, so was kicking myself a little, but still I was amazed at the progression I was making.
Now there was of course the possibility that the first girl would've freaked out by something portrayed as 'romantic' in a movie happening in real life. But who wants a girl who's scared of life anyway? Really the reaction comes down to whether she likes you or not. This girl had probably already seen me on the bus and liked the look of me, although if I was wittier I could've won her over from cold just from chating to her. And if she hadn't liked me, so what? There are so many people in the world. Accept that some of them AREN'T going to like you. Don't let them inhibit you. If they don't like you, then you have no reason to care about what they think. It is only the people who DO like you that you should care for the opinions of. And playing the numbers game is the way to find out who's one of you and who's one of them. Of course it helps if you learn to read the signs... a good book on body language helps.
This kind of thinking applies to interacting with any people, not just girls. Acknowledge that you're nervous, feel the adrenaline, and channel it into action. It's ok to be scared, when you go ahead and do the thing that scares you anyway. You'll find you actually get a real thrill out of doing it afterwards. Massive natural high. And eventually you won't get nervous any more, once your body learns it as normal behaviour.