Why don't they understand...I'm just too tired.

I've been invited to go watch the superbowl over a friends house but I'm just not feeling well today and I decide to decline the invitation.   Then it starts...that look like you really don't like all that tired or sick, can you please just go to watch the game.  It would mean so much to them (the couples house I was invited to go to)....well what about the fact that I just said I'm not feeling well today.  My mom asked me to go with her to get her taxes done.  Wouldn't you know that it starts to not only rain but a bit of light snow as well and I can just feel the my joints starting to ache and then the headache starts....I just want to go home and get in my bed.  My mom seems to be understanding but then what happens next is I just called to see how you're feeling you always seem to be sleeping or not feeling well so I never know when it's a good time to call.   My best friend has been trying to reach me for a few days now and I've been resting trying to get this pain to go away, when I finally muster up the strength to answer the phone I hear...it's about time you answered the phone. 

When did it become such a big deal to get some rest?  Why do I have to feel so guilty when I just want to get some rest to rejuvenate?  Why do I feel so alone at times as if I'm just becoming a loner simply because I want some sleep?  Am I wrong...should I push myself to do the things my body doesn't feel like doing just to please others?  I'm just so confused and feeling like I'm letting everyone down.  Anyway just wanted to vent but I'm sure tomorrow brings a better day.