I work atnight. I usualy go to gimn and then work. I usualy feel tired next day even sleeping 7hours. What can I do. Suplements food?

Poss. sleep disorder. You may have a sleep disorder like sleep apnea. I would get evaluated by a sleep specialist.
Night shift symptoms. Working a night shift affects all of your body's natural rhythma, particularly sleep. It takes several weeks to adjust to a new schedule. Thus, if this is a recent change for you, just wait longer to make the adjustment. If symptoms are persistent, then practice some relaxation behaviors (reading, meditation, music, yoga, etc.) when you come home and before you go to sleep. Best to avoid eating.
A few suggestions. The human body is wired to sleep at night and be productive during the day. It is not uncommon for shift workers to experience trouble with sleepiness. One suggestion is to expose yourself to bright light after waking up. Your doctor may suggest supplements like melatonin, which is normally produced in the body before sleep, to help you fall asleep. Exercise is not as likely to be the cause.