Hello BL thanks for the responses, wanted to update to let you all know I'm still alive and what a hell of a couple months that was. It was indeed GABA withdrawal from the F-Phenibut causing these heart issues.. I HIGHLY recommend avoiding this stuff altogether if you're considering it although admittedly I was using the f-phenibut for 5 months straight. I have been through all sorts of hellish withdrawal with regular phenibut HCl but nothing compared to this especially when it came to duration. This withdrawal made me truly think I was dying of heart complications for roughly two months (end of February til the end of last month). I was getting "episodes" of very real heart pain, palpitations & tachycardia that would usually culminate in a massive panic attack. This was daily, every day for 2 months. I am still not 100% right but the episodes have disappeared and I'm left with a more manageable form of generalized anxiety. I still can't drink more than a small cup of coffee per day and I'm still too afraid to resume my morning runs.
Several thousand dollars later all my tests (stress test, holter monitor, EKG, etc) came back negative for actual heart issues so it's all related to GABA withdrawal which is why etizolam would (temporarily) cure my episodes. As much as I tried to tell myself it was withdrawal this truly made you think it was something more, like some kind of irrational psychosis. So yeah, avoid this compound, stick to regular phenibut HCl.