M.Y.
Hi N.,
Before I write more I will tell you that this will pass. The first few teeth are the worst and it should get better after that as I was told. Depends on the baby, some babies go through teething with no pain and no fuss. Some goes through trauma.
My now 10 month old son didn't get his bottom two teeth until 8 months though he started teething when he was 4 months. We also sleep trained him pretty well and everything regressed when his two teeth started popping out. He would wake every 2 to 3 hours and waking up screaming and crying. Nothing can console him. We just rock him and hold him until he goes back to sleep. Of course for my son this also happened right when he started crawling so that also made it hard for him to sleep for more than 3 hours at a time but that's a whole different story.
Just hang in there, as soon as those teeth pop out he will go back to his normal self. I heard night time is the worst when babies are teething.