I agree about the teething... be sure to go ahead and get some teething tablets..If he uses a pacifier, put 3 in his crib so he can grab for it in the dark.
This weekend will be a good time to start a new sleeping routine.
Tomorrow evening,
Have a nice dinner. Be careful not to be too loud. As long as your child gets really riled up it will take him to calm down. Sometimes twice as long. Turn off the TV and cell phones.
Bath time should be quiet, and the house slightly darkened so that it does not look like there is anything interesting about to go on.
During the bath, have really warm water and use strong rubs like a massage. Then wrap him in his towel and carry him into a slightly darkened room. Dry him with strong strokes, use quiet voice tones. Breast feed him or give him his bottle while you read him a story.If he has a bottle, lay him in his crib while he drinks. When he is finished with his bottle, rub him slightly while you read. Read slower and slower while reading. Do not engage him with the book. Do not ask him questions. He should be pretty worn out. Turn on some soft music or use a sound machine. Turn off the light and leave the room...
If he wakes in the middle of the night, give him a few minutes, he may settle down. If he needs to have a diaper change, change him in total darkness, no conversations, then lay him down and he may go right to sleep. If he needs to breast feed do it in the dark, no conversation. Or make sure you have a bottle ready so you can give him a small bottle.
In the beginning getting him to sleep on his own may involve some crying. Just close the door and check on him in 5 min. only if he is crying. do not touch him, just peek and tell him "it is time for him to sleep". If he cries again, give him 10 minutes. then 15. etc.
Sometimes starting this new routine is best on the weekends cause there may not be much sleep for anyone in the house.
I am sending you strength.