Unless you test your battery for amperage not voltage, you could have killed the cold cranking amps to make the solenoid throw the starter. Bring it to an Autozone or local shop to fully test the battery or I have to agree with SW_Radial, it could be the solenoid.
Take one thing at a time slowly and you will figure out your problem. Getting the starter out and testing it on another battery is a good start, which is what I had to do on my 69 C10 when the starter went bye bye after driving it through three feet of water...
Good luck
