Anxiety is more when you get very nervous being public with people, or are paranoid, or in your case, a class presentation would be nerve wracking. Along with these feelings, it comes with very bad stomach aches that resemble the "butterflies" in your stomach. Some peoples hands shake, or they can't sit still. Once they get nervous about something, they dwell on that thought over and over until it drives someone into a pure panic attack.

I know, I have bi-polar and know all about anxiety stuff. It got so bad for me once that I stopped sleeping, literally.

Sounds like you're having something like social withdrawl. Smoking cannabis can do this to some people, or, maybe you're just tired of the same old boring thing and people.

Did you smoke cannabis when you found yourself more "goofy" and "outspoken"? Maybe consider cutting down on your usage to weekends only.

Try and be more social with friends, or consider a new hobby.

If this bothers you that much, consider seeing a doctor about it, but if he prexcribes you any prescription drugs right away, go see someone else. Too many doctors these days are tossing out anti-depressants and anti-anxiety meds. like they're candy. After 1 or 2 visits is not near enough time for a proper evaluation on what could be wrong with you. Just keep that in mind.

Also remeber if you are a developing teenager, that these feelings are normal for someone that age. Nothing may be wrong with you and it could just be a social withdrawl phase.

Like I said, if you smoke a lot of weed, mayb cut down a bit. Force yourself to hang with your friends, or go meet some new people in a crowd.

Just don't isolate yourself from people. That can lead to depression and gives a person too much time to think, and yes, too much thinking can be a bad thing.

And yes, I forgot to mention, you could just be maturing and growing up. Maybe goofing off and not staying on topic seems kind of stupid to you now. It would be silly to me if I saw someone acting like a goof in class. I'd think as them as, well, a goof.