I just replaced my fuel pump and now my gas guage says 1/2 and its full, i 2x checked the connection at the sending unit, wtf?

 

Maybe you bent the bar the floater is on? This is pretty common for the guage to mess up after a fuel pump change.

 

just changed my pump out also, had to bend the pickup to match the old, but everything seems to be fine, found this web-page that will tell you how to check with ohm meter, hope it helps. did you drop the tank or go in from the top.
http://shbox.com/1/4th_gen_tech1.html

 

did it from the top with a sawzall, then put plumbers goop around the edge so it wont rust even though i dont drive it in the winter, it worked out great cuz the float fell off when i put the sending unit back in