Hey panicfree,
heeh I was reading your post and I thought, geez sounds familiar.
I'm in university now. Most of the classes are huge so I get to just sit back and take notes. ( I still try to sit in the back close to doors. my brain likes to tell me what will happen if there's a fire or an earthquake and 300 people need to get out right away

) But there is one class that is much MUCH smaller, and it just so happens that it's the most important class I have. I hate sitting near the front too. All those eyes burning into the back of your head, you feel like the teacher is always looking at you like " WHY DON"T YOU SAY SOMETHING!!" and then you do and even if it's the right answer and you articulated it perfectly you still feel silly for some reason. it can be nerve wracking.
Everyone else was suggesting working on it, trying to participate and it'll get easier, and it will. Baby Steps and all. I would suggest talking to your teacher about it as well. Just let them know what the deal is, especially if it's sending you into a panic attack then maybe they can help. like calling on you when the answer is obvious to give you a chance to get it right and build up confidence. I don't know.
One thing that has really helped me in this class though has been my buddy Taylor. We met on the first day and have been friends ever since. Taylor is a natural cheerleader. He's bursting with positive energy. Literally! All year he's been there with a fist bump when I answer anything in class, the morning before an exam we have a hardcore exam psych-up. Point is if you have someone around you that you know, and who can be a sort of support it makes things a lot easier for you. if you don't have a friend sitting near you in the class just talk to the person next to you. ( you don't have to become best friends, even if you're class-mates for just that subject) But if you're positive and they're positive it becomes easier to forget about other people in the class and what they may be thinking. I know it can be hard being shy as well, but simple questions like " hey, did you read the homework? what'd you think?" or " how's your essay going?" ( and then be sure to introduce yourself and get their name. I can't tell you how many times I've started talking to someone in class and i never get their name and then you have to fake it until you see their name on an assignment or the teacher calls on them or something because you're too embarassed to go ' Hey we've been chatting for a few classes now, but I don't know your name' so awkward

)
anyway I don't know if that helps at all. hope things get better for you. good to know there are some younger folk like me on here too.