I haven't been boxing for about 4 weeks as i have been on holiday, and the past two days when i have been i have been so tired and feels like my skills have gone down hill. Is this due to not doing any exercise or anything while i was away. Will it come back?

Of course it'll come back. Provided you come back, of course. ;)

I haven't been boxing for about 4 weeks as i have been on holiday, and the past two days when i have been i have been so tired and feels like my skills have gone down hill. Is this due to not doing any exercise or anything while i was away. Will it come back?It'll come back after a few days. I missed a week for vacation and when I came back, my performance on the speed bag was horrible and I was getting ready to puke after rounds on the heavy bag and jump rope.

You'll be fine and back to normal after 1, 2 weeks at most.