Probably Screwed up my Derailleur shifting from 1-6 without pedaling So I've had this problem for a couple months now, what happened was I was being stupid and seeing what would happen if I shifted 1-6 without pedaling... As a result, the shifting now is screwed... The bike will say 3rd gear but be in 5th (I don't think it will go to 6th). It only goes up to what it says is 3(actually 5) I can still go to first gear but it won't display any number because it already passed 1(which would be gear 3 I think). Also the chain has been slipping on the highest gear whenever I pedal faster or slower.. It seems to disengage for like 1/3 of a second and I lose my foothold on the pedals. Any advice? Any thoughts on what's wrong with the Derailleur?
Sounds like one of four possibilities.

1) Pulling on the shifter has bent the derailleur - very unlikely unless you're a gorilla or the derailleur was already bent/weak

2) Your gear cable outer is weak somewhere and the extra tension has caused it to collapse, which effectively makes the inner longer than it should be.

3) (was 2b) Your shifter was weak and has bent or the number indicator has moved/bent.

4) (was 3) Most likely, you've stretched or pulled the cable through the adjustment bolt on the derailleur mechanism.

Hang the bike up on a repair stand, or use rope/cable/something to lift the back wheel clear of the ground.  Use your hand to slowly pedal and pull the exposed gear inner wire with your other hand while pedalling.  The gears should change like normal, through the full range.  If this works, then the inner wire is too long and needs some slack pulled through the adjustment bolt on the derailleur.

See "four rear derailler adjustments" section at http://sheldonbrown.com/derailer-adjustment.html   for details on that.