skin brushing makes me nauseous

hi,
i started skin brushing, and i love it! but towards the end and afterwards i feel a bit nauseous, also it makes my wrists ache and some other joints as well.
i am assuming this is some kind of detox reaction? or am i doing something horribly wrong? also, can you skin brush for as long as you feel like it or have time, or should sessions be time limited?
thanks,
cyclo Tweet