I get like that too....i actually go do things with friends and they say we HAVE to do this again...and then i never hear from them again.
I hope this is not what happens to you...ppl don't understand how hard it is for folks like us just to BE social! I force myself...just like you...to try and socialize...i am a loner...but i don't like it all the time.
Either way...don't let it get you down.