Here are some details..
I was on a 4.4.2 KitKat ROM (Gummy Nightly) and decided to try out SlimKat 4.4.2. I wiped (advanced wiped System, Data, Cache and Dalvik Cache). I proceeded to flash the ROM and then the gapps file. Nothing out of the ordinary.. I rebooted and noticed I was at the samsung custom screen for a little longer than normal.. I didn't begin to worry too much because sometimes this screen can appear for a little bit before continuing when first booting into a fresh ROM install. Well.. quite some time passed and it became apparent that it wasn't going to go any further, I restarted the phone and consistently got stuck. I tried booting into TWRP and couldn't/can't get past the TWRP Blue Loading screen. I tried letting it sit for a long ass time (1 hour +) and same with regular rebooting at the Samsung Custom screen (1-2 hours +) with no luck or change.
I have a backup but can't get to it obviously. I'm quite frustrated and am confused/worried about attempting any drastic measures because all of the different phone versions/bootloader discussions/issues. I don't want to mess up the phone by bricking it or something when trying to flash the wrong file. I believe that right now the only thing I can do, if anything, is connecting my phone to my computer via a usb cable and running that ODIN program? I'd be inexplicably grateful and appreciative if someone can just give me some steps/instructions so that I can get my phone back up and running. I'm without a phone right now and am stressed out, so I'm hoping that I haven't made too many people upset with me if there's already somewhere this is answered. I searched but can't find someone with the exact variables my situation contains.
Phone will not progress past samsung custom warning screen as well as TWRP Blue Logo screen no matter how much time passes (Have let sit at either screen for hours)
Was flashing SlimKat nightly (the most recent two days ago) coming from Gummy nightly (1-12, I believe).
The samsung custom screen comes up and then the phone reboots 2 seconds later and comes up again etc..
I never had to use 'safestrap' or whatever. When I got my s4, I was able to avoid the update and was always able to flash ROMs without any worry or concerns.
Please XDA, Help me out here.. I'm completely stressed and worried and don't know where to go from here.. What files to I manually push from my computer.. I don't see how I can solve this without a computer because recovery wont load and ROM won't either