I managed to solve this problem, though I am still struggling with the PATH_INFO problems, no solutions seems to work for me.

For those who find themselves in the same situation, my suggestion:

Backup:
/concrete/libraries/request.php
/config/site.php
/php5.ini
/.htaccess
/packages/* (Full folder content)
/themes/* (The themes you use or you want to use)
/languages/* (In case you have a translated C5)

Change site.php to bkpsite.php or something, so you can download the new one over it, is a great thing if you changed yours.

Just delete everything in the server and unzip c5 again. Go as if you're going to make a clean install and start making the changes needed until everything is green.
For that you'll use your backed ups request.php, php5.ini and .htaccess

============================================
NOTE:
The .htaccess can take a long time until it works. A pain in the ass, I know, but bear with it, don't make a shitload of changes, wait patiently. Trust me, it will save you later.
============================================


Then simply download the new site.php and compare yours to it. Apply the configs needed to make the site work and it should be working in a handful of minutes.

Should make everything work again. Easiest way to roll-back anything that breaks your site.

Remember to upload packages, themes and languages folders, so you can get everything back the way it was.


Good luck everyone. ^^

for anyone else inquiring, I ran into this as well, and my solution seemed to work just fine:

1) go to your hompage and login. uncheck pretty urls, clear cache.
2) delete your .htaccess file (you may want to copy any non-pretty url info)
3) log back in to your site and turn pretty urls back on.
4) double check that the new .htaccess file was generated. if not, add it and paste the new snippet in.
5) turn your cache back on.

ChadStrat

If only I could log in to my site.