R.M.
My grandson is almost 7 months old and teething, his favorite treat right now is to have a cold baby carrot, straight out of the refrigerator to gnaw on!!! He can't really "eat" it but it sure makes his gums feel better!!!
I know that teething can cause so many problems....lack of appetite, loss of sleep, diarhhea, and even cold symptoms. Just keep trying things and you will eventually hit on the magic formula!!
Have you used Hylands Teething tablets? My daughter swears by them...says they really helped a LOT!!