Did you ask your doc for some ideas of maybe something you can take short term to help with the tummy troubles?
How long have you been on the Celexa now?
Some people are just more sensitive to meds, and the side effects will be a little bit worse. If you could manage those symptoms (even with something OTC like Simethicone...an anti-gas/bloat medicine), it may get you feeling a lot better until the side effects resolve.
I would ask your doc, see what he says.