I was told me to stop wearing my retainer during school. My teeth still feel a little unstable though-I don't know what to do?

If you feel uncomfortable taking out the retainers, then wear them 24/7.  It does not hurt at all to continue wearing the retainers all of the time.  You may want to ask your dentist/orthodontist to see why the retainer feels really tight after removing them for a while.

The process of braces is amazing.  Pressure is applied and the supporting bone softens.  Teeth move, and then pressure is no longer applied.  When pressure is gone, the bone hardens.  But this takes time, so a retainer is needed to "hold serve" until bone is dense.Eventually, the bone will be stable.  While movement may still happen during the day, the amount of movement will not be much and easily corrected while wearing a retainer at night.  Retainers should be viewed as a lifetime commitment.3 months after braces have come off should be enough to transfer to night time use only.  While you CAN wait until 6 months, the difference likely won't be much.Or you COULD simply commit to wearing a retainer 24/7.