clutch engagement question.. clutch burnt?

I noticed the other day when i would stomp on the gas in second gear, the car would rev up to about 5k and then come back down to about 4k before really pulling (such as the clutch slipping). i have a firewall adjust clutch cable and i turned it clockwise completely untill it stopped at the firewall, but the clutch is still doing the same thing.. is this a red flag for a fried clutch?

thanks