started exercising - feel weak ugh

i started doing DAnce Wii  a few days ago and after i did it today for about an hour off and on with my son, now i feel weak.  my arms just feel exhausted and i feel soooo tired.  i was helpingmy friend watch her little girl who was sick today - not really around her but watching her in her car while she did something inside cause she wa sleeping - then when she woke up she was coughing bad.  anyway now i'm obsessing about her germs and maybe that's why i'm feeling this way.  sooooooooooo ridiculous cause i'm sure i didn't get her germs.  it was super windy outside and i wasn't directly in her coughing. 

anyway anyone ever exercised alot and feel weak afterwards?  i usually don't but we were dancing alot using our arms.  plus my son just left last week for basic training and i'm a little stressed.  you know moms - worried about our kids.  i know he's fine but i'm not.  haha 

thanks kitt! yes i know it's probably just muscle fatigue but here goes my health anxiety. i also didn't get enough sleep last night. me and my son went to the drive in movies (fun - he'd never been) andwe got home late - and you know kids - he woke up at 8 a.m. even tho he went to bed late. can't get him up when it's time for school but on sat. and sun. yep! makes no sense! haha

i am sooo out of shape though - i'm feeling it now for sure. i want to get in shape so bad but when i start out hard like this i feel like crap exactly why i can't do the p90x. too much for me.

how are you kitt???? thinking about you. :)