Is it normal to have an increase im size of just one breast before periods?

It depends but yes: Increases in the sizes of breast does occur during menstruation and is completely normal. Regarding just one breast, this can also be normal to a degree. As long as one breast is getting bigger and then smaller and not just getting bigger and bigger, then you should be fine. If it is getting bigger and bigger or if you feel a lump during a self breast exam then please see your doctor.