My teeth feel loose
This is very common during orthodontic treatment. You should not worry!
Your teeth have to loosen in order to move during brace treatment. They will firm up once they are in their new position. It is also quite common for the degree of mobility to vary throughout treatment. Therefore, teeth that are firm may become loose and those that are loose may become firm in between visits.
It may also be helpful to limit your diet to soft, easy to chew foods. Loose teeth can also feel a little tender.
If you feel your teeth are excessively loose, contact the practice for an earlier appointment.