I caught it when I was 24. you should feel better after about a week and less spotty enough to go out a week after that. Didn't seem life threatening at the time.
I got Chickenpox back in November (at 32) off my daughter
Felt like death warmed up for 2-4 days but other than the itching was able to work at home after that.
Top tips.
Bicarb of Soda (loads of it) in a bath.
Phenergan for anti itching (and if you take the sedation dose helps you sleep)
Hit Brufen and Paracetamol as well to relieve itching and fever.
try try try not to itch.
I was off work for about 2 weeks (until I was not infectious any more.
Oh and the worse bit was spots on face in amongst the beard that ends up growing as you cant shave.
Good Luck
It generally can be worse if you are an adult, you may well feel horrid for a few days like stodge says - don't try and do anything until you fel better. If you take an antihistamine it will help reduce the irritation - and if you take the old fashioned sort it will make you sleepy too! which will be a bonus until you feel better. Keep away from elderley relatives as is can give rise to Shingles.
Catching shingles from someone with chicken pox is a very common misconception. You can catch chicken pox from shingles, but you can't catch shingles from chicken pox - it's a reactivation disease like a cold sore is, it hits you when you're down. You can only get shingles if you've already had chicken pox.