Steve is correct, you're likely on a visa exempt (short term tourist w/30 day extension. Not an extension visa) So no big deal, Laksi advice sounds accurate.
You don't mention type of stamp or if you're leaving temporarily or not so cannot answer. I would do what Bangkok I.O. told you to do if a tourist just going home.
Not enforced but immigration may stop/refuse you if you're abusing the term/visa 'Tourist'. They want you using the visa that applies to your real situation