So finally solved! Thanks heaps to CustomRomAddicts and XxPixX for the help!
Just for anyone else stuck in the same boat:
Problem: Phone won't boot, stuck at the flashing samsung logo.
Tried and didn't work: remove sim, remove memory card, different battery, on charge, off charge.
Solution:1) Installed Philz kernel (found the kernel I require by looking at the stock rom code...mine was DDLSC) on my external SD. You can find this out by looking at the stock roms downloads on Dr. Ketan's page and finding out where you got your phone from in the first place (assuming it wasn't parallel imported).
2) Put the external SD back in, go into recovery mode (vol up+home+power), backup whatever I require (which in my case was a full backup).
3) Factory reset. (Mine did not delete the pictures, songs etc. It did delete all contacts, sms, call logs, applications, settings and updates).