How to not feel anxious/nervous about everything

So recently i’ve started becoming really anxious and nervous to do anything. It ranges from things like going to appointments (nails, hair etc), filling up my car with petrol, going out for meals and even seeing family and friends. I get this nervous feeling in my tummy and it feels like i need to 💩 all the time. I feel worse when i go out for meals as im worried that im gonna get food poisoning or become ill, and then because i get so worked up about it, i then do become ill.

I have my 21st birthday party tonight and i understand people would be nervous and excited for this but im at a level where i dont even feel excited for it cos im so worried and nervous for it that i already feel so ill, and because im gonna be drinking im worried that’s gonna make me ill so im going to try not drink too much.