I would suggest that you do some or all of the following.

Ask your teacher to change your seat if necessary.

Learn to count to ten if something is bothering you and then keep on counting if necessary.

The school knows your problem. Ask then to select teachers for you that you tying that you can get along with.

See your guidance counselor. Some schools have a peer intervention program.

Obtain counseling. Whether you think so or not you need it.

See if your parents and friends can come up with suggestions.

Good luck in the new term.

Step 1: Go one hour without telling anyone off.

Step 2: Go one morning/afternoon…

Step 3: Go an entire day…

Or if your undesired behavior is fidgeting/talking/spacing out…whatever it is, make quantifiable goals and track yourself. You can unlearn a bad habit. In education it’s called Behavior Modification.

http://www.coun.uvic.ca/learn/program/hndouts/reinf_ho.html