i find it interesting you (mr snuggles) are an infj who feels a deep need to socialise and have more friends. Im the same type but im relatively happy with virtually no friends. i suppose we are in different places in life.
I feel there's little point telling you to 'just relax' or 'try to stop worrying', because from personal experience, it is best just to let yourself worry and be stressed if thats what your body wants to do. it is better to try to figure out the exact reasons for stress and try to combat them.
ive gone off point a bit. I guess my point is i feel like you (mr snuggles) may be going through a difficult stage, but i'm sure your relationships with people will improve given time. You will have ups and downs of self esteem, but just remember when you're languishing in a down, an up is right around the corner.