I experience something quite similar. It can be really frustrating sometimes. I think that Claritytoo had some good suggestions; I just wanted to add another thought: Sometimes it is hard to see that grounding techniques are working because dissociation is partly a physiological mechanism that can take time to go away even with grounding. Honestly, what works best for me is time. Sometimes episodes are really bad and I can barely move or talk, but if I try to keep myself comfortable and have something pleasant to do, slowly the dissociation gets better.