I used to box a while back but have moved, there isn't a close boxing gym close by to me and i decided that i wanted to join the local Gym, so i have dont and i been there today, i did a routine witch mostly involved strength training and i'm trying to build muscle! So when i went to the gym today and did this routine (can't be bothered to explain it all) i have come home and i feel so weak and i can't ever remember feeling weak after the gym when i was boxing!?

Is this Natural...?

You havn't done it in a while and are unfit. Thats whys. Keep at it and the rewards are there.

your body is exhausted. you havent been physical like that in a while like you said so your body is going to be tired from those kind of workouts for a few weeks until it is conditioned to handle it.

Cheers just making sure i wasn't dying or something like that lol!