composite fillings and chewing gum

unfortunately I have to get 2 (I think?) fillings due to having "deep ridges" in my mouth where food gets stuck and I'm not able to brush my teeth when out in public (obviously I didn't know about my back teeth as its looked the same since over a year and nobody said anything to me), I'm just scared about the drilling but apparently it's so minimal for my decay that it won't be too deep to drill (I hope), I'm scared the tooth will be sensitive due to the drilling and that decay might get stuck under it from drinking juice etc and the filling capturing it and making it worse, so I'm wondering if I can chew sugarfree gum or will it damage the filling, and also any other advice for how to avoid breaking the filling? I'm also scared the tooth may crack due to the drill.. this is my first filling in my adult teeth and I'm quite young so I know it's really bad but other children my age have alot more fillings so I'm glad that I don't have that many, atleast...

the noise is annoying but as long as you have enough anaesthetic its not so bad to have a filling done. once it sets you can use it like it was your real tooth

ah ok thank u but some people say that they can crack ur tooth with the drill, and also that the filling can break off with chewing stuff like carrots..