Sucks to hear man
but don't give up on her just yet!
Which areas did you treat with POR15 though? I'm not really seeing any on the undercarriage?
You still have options, such as having new sheet metal welded in + paint. You can then take it to a shop and have their rust prevention treatment done in the door jams, frame, and other nooks and crannies.
Might still be much less cost than a new ride, if everything else is in good order? If $$ is an issue, get yourself a small personal loan from a local credit union. Could probably pay that back in 2 years and have a "free" rig again?