Hi,
Not much advice but lots of sympathies. My almost five-month-old has just got his first two teeth. He was fine until yesterday.
If you can try and take a break. I have found being on my own with him very hard at the minute because I currently have a nasty chest and water infection.
Mine has had extra feeds, lots of cuddles, screen time (all hail Miss Rachel) and some Calpol at night. He doesn't do teething rings but loves eating his hands.
I've heard good things about Parsons gel and you can take that with Calpol. I have heard that Nurofen is better for teething though.
Just a picture of a toy we have. He loves it for his teething and prefers it to any teething ring I've ever given him.
During the day we just do his favourite things. He is currently sitting on my lap being cuddled watching the lights on his play gym.
On another note, watch out for runny poo and a bad belly. I didn't realise they were related until I saw the teeth and then his poo went back to normal.
Unfortunately, every baby is different and this is just what is helping mine.
Good luck and I hope it's over quicky.