Hello marcymarc.  No you are not going mad - you are just being a normal human being who like most of us worries about things even when all the evidence tells us all is well.  The trouble is that these worries can obsess us and stop us living a normal life.  If we were going out, doing things and  getting on with life generally we would be feeling a lot better.  To be honest I am not sure where you should go if you want help to get over this but I would seriously suggest you push yourself to get on with the things that a 23 year old should be enjoying - then I think the fears in your mind will start to drop away.  I can only speak from personal experience - I feel better if I get myself out, walk the dog, interact with others and take an interest in their concerns.   Best wishes.  Annie