If you're terrified, it means you're panicking. If you're panicking, your brain is just going to ramp up the tinnitus because it thinks it's doing you a favor by sending out the noise alarm. Please consider medication short-term. Xanax has been a godsend for many folks on this forum, but of course be very cautious with it. Take the least amount possible and make sure you taper off. Never stop Xanax cold turkey; it's the worst thing you can do.
As for the tinnitus starting up in your other ear, that's just the unpredictability of tinnitus. It will bounce around like that. One ear, the other ear, both ears, the middle of the head, top of the head, back of the head, sometimes everywhere together. Again, try your very best to distract yourself.
Right now I have a freakin' wasp swarm in the upper right quadrant of my head. It's been getting louder as the day goes on. I can't get any work done, but I have managed to deal with it by messing around with word apps on my Kindle, trying to read, watching Netflix for a couple hours, washing dishes, calling a friend and just chatting about the day, plus I took my dog to the chiropractor and was so focused on her during the treatment that I actually didn't notice the tinnitus very much at all. Unfortunately, the treatment only lasted 10 minutes.
Someone on this forum once said that if he threw a cobra on your keyboard, you would totally forget your tinnitus while dealing with that emergency. In other words,
it can be done. It takes a lot of mental discipline, but what you have going in your favor is that the tinnitus is still new. Don't underestimate your strength to deal with it.