Teething?

My baby is almost 6 months old, we think she may be teething. She has been having diarrhea, more fussy than normal, and struggling to go to sleep at night the last couple nights. Is it normal for her to be eating significantly less formula than she usually does? For example, she typically will eat 5-7oz 5x a day with a total of 25-30oz, but the last two days we have been struggling to get her to eat 2-3oz at a time 7-8x a day for a max total of 20oz. Is this typical? We have already been in contact with her doctor but just asking for others experiences. When should we be concerned of it is normal?