oh then i think your be fine, i would only say watch it if you were going a lighter colour. is it a perminant dye or wash out after 6 washes? if its perminant i would leave it another week or so. if its 6 weeks then go for it whenever.
(i dyed my hair purple, pink, blue etc etc but never with perminant so wouldnt know how long to wait for sure on that account but 6 weeks is fine to just dye it again now.)