I took add medicine and i think i am pregnant could that effect the baby?

Not necessarily but: Speak with your obstetrician and whoever is prescribing add meds and be sure they are collaborating.

The whole point of: Medications is to alter body function(s) in various ways. Thus, of course, it could affect the baby. However, the issues are complex, remain not that well understood, not because meds are complex (they are typically just single molecules) but humans, our biochemical structure ; multi-level control mechanisms are fantastically complex, often compensating, at least partially, for many issues.