I started playing WoW again about a month ago after taking a break for I'd say 2-3 months, I was undergeared for the normal and heroic raids of last tier so I was even more undergeared when I got back, however last tier my guild and I were able to progress to 5/16H, prior to that in Cata I was 8/8H for quite some time before MoP. I really like heroic raiding, it's probably the only fun thing I do in this game, but about 2 weeks before ToT came out my guild split due to raiders not being able to raid and I just quit for a while basically said "fuck it", which is my own fault but now I find myself stuck. I can't join a guild I want to because I don't have the current experience and no one takes your word when you say "I'm not a drooling moron", also my gear is pretty bad even after running LFR several times I haven't gotten anything, but I still do over the amount of DPS my character is Simcrafted at and I know that doesn't make me the best raider to ever roam the earth nor am I in any way trying to say that.
TL;DR - I'm stuck with no guild, I'm not bad, I need suggestion/help/ideas on what I can do to get going again.
Well all I can recommend is just keep gearing as much as you can but don't worry so much about it. Patch 5.4 is due to hit live servers in about a week or so which will unlock new LFR gear and flexi-mode that you can pug for upgrades. That is probably your best bet. Also, depending on your economy, you can save up gold and maybe find some BoE's from SoO or even find groups that do trash runs if that will be possible (<-- not sure on that since I haven't kept track on SoO). That also applies to crafted epics. There will surely be some new crafted epics available in 5.4 so you can see if you can get your hands on the materials.