Opps, almost missed his age. If he is almost 8 and in second grade, I take it his birthday is late Oct or Nov. He could very well be the youngest child in his class. In California, they just passed a law that says you must be 5 by Sept. to enter Kindergarten.
Anyway, this could also partially be maturity. And he is tending to stand out more compared to the other older children. If so, it should get better.
Several reasons why a kid may go to the bathroom that many times a day. Stress or boredom are usually the main candidates. Allergy meds can also cause problems with urination. He could be looking around because he is bored or is trying to figure out what the kids are doing/were doing since he left.
Main question is what was he like last year and the year before. If this is only a problem this year, then its probably not ADD or autism.
Being bored or antsy in class does not make him a candidate for drugging. Lots of children are like this. They outgrow it. Psychologists seem to have established a "norm" for childhood behavior, the "norm" being an attentive and cooperative child who likes school and works hard at it. HoHum.