Awww you poor thing, you're having a rough time of it, no wonder you've felt exhausted.
I had the can you get chickenpox more than once saga a few weeks ago when they thought I had it - I had it badly as a child but in the few days it took them to do the tests to see if I was resistant I was kept in hospital on an antiviral drip just in case (dangerous with the immune suppressing drugs I'm on).
My GP said medically you aren't supposed to get it more than once but they come across quite a few patients who say they have - I even had medical students come to look at me as apparently chickenpox diagnosis isn't always as straightforward as it may seem.
Not sure what it was, my body just having a laugh probably, I think it just gets bored! ;)
Take it easy and rest up as much as you can, could be a viral rash or something