RPM's decreasing ?

Ok so here lately it seems that my truck shifts into 2nd sooner and sooner.
When I first got the cam it would have the tach buried for quite a while then hit second and im pretty sure Nelson said 6500. ive slowly noticed it shifting sooner and sooner til tonight I noticed it shifted right at 6k or possibly even 5900. Is there something that could be causing this?
Or am I just being parenoid?

Is this happening at WOT?

maybe the carpet is getting in the way in the back or just not flooring it all the way...i have seen it happen before..

Yea it is at WOT, and Flaco thats the exact same thing I thought at first before I posted this but diddnt wanna say I tried it.lol my floors and mats are out of the way.. Ill post vids up later of before and now.