Oh dear is right. Another very complicated situation.
The grapefruit seed extract could be acidic in which case you will be leaching mercury when you are swishing that stuff around.
Heavy metal poisoning may underly the infections you mentioned or not, who knows, but there are some theories floating around that they are linked. And it will explain why you haven't made permanent progress since you have not addressed the metals problem.
I would say do not do flushes yet until the molar has been removed and you are stable. Just try to keep as stable as possible until that chunk of poison is out. Mercury root canals are especially insidious.
And don't listen to the newbs here who can't get a good night's sleep or can't take a shower without collapsing - they have a long way to go before being qualified to advise you. Mikey-the-newb will be along in 3-2-1 seconds about how he got his Amalgams removed and then nothing happened.
Getting my Amalgams out was a big step in recovery, not easy but necessary in getting the proper intestinal flora back.
Study up on Andrew Cutler/ Dietrich Klinghardt and the other forums here where people are knowledgeable about heavy metals.
You could also just pay out of pocket for the molar removal. If it's just one then it might be affordable. I'm sure Ukrainian dentists are reaaaaalll cheap :)
I have gotten my Amalgams out, chelated, solved sleep and energy problems, so when they start calling me troll! troll! just remember who has experience and who does not.