I started getting the feeling after being re-traumatized badly. I also have ptsd. I've yet to find any kind of grounding that helps with it, I have to just ride it out. What I've been doing lately though is watching the second hand on my watch and counting while focusing on breathing. It really doesn't do much but put time into perspective so I can focus. I still float around though.
I understand your frustration with all this. I too have little to no support. All I have is the internet really and it's been that way for a long time.
Things seem hard now but they will get easier as time passes, at least it seems to be that way. I wish we didn't have to deal with this crap at all.