I know what you mean hun, i am constantly meeting new interesting people, and it is so hard to make time to cultivate frienships with these people while maintaining the important old long lasting friendships and at times i do slip up :(
Its like an added responsibility to hold onto old friends, building relationships with current friends and continue to meet new friends. But hey, its all well worth it! (especially when you drive an hour and a half to have dinner with COOL friends, then come home and get 5 hours of sleep for service the next morning)