Digestive problems are one of the most common symptoms of antidepressants. If the drug is working for you otherwise, you can try remedies such as aloe juice and digestive enzymes. If it isn't working for you, then yes, you should try something else, but taper slowly and work with your psychiatrist when doing so. If the psychiatrist doesn't seem to understand or empathize with withdrawal problems, find another.
It could be from the medication in my opinion. We all react to meds differently. Have you tried taking it at different times of the day or with a full stomach? Have you been taking other medications that might be giving you this as well?
There are so many factors to consider it can be pretty confusing. When I would have side effect questions I would usually go talk to my pharmacist and/or doctor to see what else I could do...keep us posted!