Should I continue with wearing my new 5th tray of Invisalign if its not fitting tightly?

Hello, I am doing invisalign express. Last night I went to switch to my 5th tray, as it had been 2 weeks.They mostly fit fine, but the very back of my top tray on the upper right wasn't fitting tight to my teeth. I know I have it all the way on. I wear my trays 20-21 hours/day. There may have been a couple days I wore them 19 hours. Also, about a week ago, I unknowingly took my upper tray out while I was sleeping. I have no idea How long it was out. Should I keep the 5th tray in and hope my teeth shift into place? Or wear my 4th set until the 5th tray fits better?