Hello, recently, while working out at the gym, i seem to have hit a heavy sandbag against the back of my head, or at least i think i might have. ever since, i feel dazed & confused and have been experiencing a mild headache in the back of my head?

If the headache continues at the back of the head, with dizziness, you should see a neurologist to assess for any neurological changes. For instance , numbness on one side, mild loss of coordination on the other, changes in swallowing , change in pupil size, could be the result of injury to the vertebral artery .

Seems unlikely that you had a concussion, but the symptoms do suggest post head injury problems. Safest to have your doctor evaluate this. Not feasible to pin down further from your post.