OP The reason it appears worse at night is because everything else (in general) is much quieter at night. I've had Tinnitus in both ears for almost 20 years and have found that stress will increase the noise, so I've had to learn to remain calm...sometimes easier said, than done. I have a radio or music playing 24/7 as white noise and find this helps a lot.
I would imagine if the doctor thought there was a risk of other problems they would have warned you and while I'm not medically trained can't give medical advice, but for me, I would try (very hard) to relax, not drink alcohol (makes the noise worse) and maybe take some paracetamol to make me sleep.
I've also found some foods make mine worse and I've almost given up on alcohol totally, it's just not worth the noise that follows. If another of my medical problems is about to flare up, then the tinnitus gets louder too, kind of like an early warning system, this also happens if I don't get enough, or interrupted, sleep...thanks to the neighbours 2 x barking dogs.
Not everyone has the same symptoms so test these for yourself and take note if they affect you, then you know next time. Just prior to Xmas I had another hearing test and was told my hearing is perfect it's just the noise in front of the hearing which is a pita.
Do hope some of this helps and please try not to stress....I know this is easier said than done, specially when you are worried and newly diagnosed. In the beginning I thought I would go mad but as I've learned to accept it and relax, most days it's a lot better than it used to be, although there are often trigger events at times too.
Wishing you all the best and hope it settles. ;-)