I think a lot of making friends comes with putting yourself out there. I understand you've been hurt in the past, and you want to protect yourself, but that same action seems to be ending up hurting you now. The first thing I would suggest you do is work up to putting yourself out there. Maybe start with smiling at people and saying "hi" as you pass them in the hall, or go into class or something. This is good, because while it is helping you get more comfortable, it is also making you look approachable, so others may come over and strike up a conversation too. Just work up to chatting with people. Once you can make small talk, it can go reaaaaally far into helping you get new friends. If you feel like you may freeze, perhaps think up a couple topics beforehand that you can fall back on. Just until you get more comfortable.

Another thing I would suggest is joining a club, or something similar. Usually they are centered around a common interest, and that right there can give you something to talk about. Or maybe sports, if that's more your style. Usually teams are a good way to make friends, because everyone is working together all the time.

It sounds like you have someone who wants to be your friend, so even though it might be scary, I would really work towards becoming a good friend of his. If you feel comfortable, maybe you want to tell him why you think you are very quiet, just so he understands and he won't push you. Otherwise, I would just work on building things up slowly with him too. Talk a little when you see him, and then build up to more and more talking.

All in all, I think it's a process to get back to being more outgoing and having more friends. I know it was for me. But if you just take some baby steps frequently, I think you should get there.

I hope it works out for you! =)

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I don't mind, I'm still free
You can't take the sky from me