I'd say reboot first, which you may have already done, next check your display settings and see if the increased touch sensitivity may be on, and if that doesn't work, maybe a factory reset. Beyond that, maybe a warranty or insurance claim. Hope you get it worked out.
Edit : I forgot to say you also could try a different keyboard. Check out SwiftKey, and SwiftKey beta. Both are very good, and the beta will let you put the number row at the top.