Got filling 2 months ago - back molar - still feels sensitive when i eat very sweet foods. what could be the cause? faulty filling? shld i make appt?

Yes: Contact the dentist that placed it and discuss your symptoms. Usually sensitivity to sweets means there is plaque present around sensitive dentin. Try cleaning the area very thoroughly . In the absence of plaque, sugar does not cause tooth sensitivity. If you have sensitivity to water as well, there could be a defect in the filling.

Imo: sensitive to sweet may, i said may, indicate there is still caries( decay ) present , or a void in the tooth-filling interface. Also if you have recession , the root surface can be more sensitive though at 24 yo not as common... Another possibility, it could be an adjacent tooth to the one worked on . As previously advised, contact your treating dentist for guidance.