How on earth do you know if your breastfed baby has diarrhea?

I am beginning to suspect my girl has had it for over a month! She is 4 months old, about 2 months ago she started a new reflux medicine that can cause diarrhea, I also entirely cut out dairy and soy as I suspected she was allergic. Her symptoms improved so I tried reintroducing soy 1 month ago and she started having very mucousy stools. Some had a bit if blood. I cut soy out immediately but her stools have not improved.

She has bowel movements 4-7 times a day! And almost every one has lots of mucous in it. (No blood) Is this diarrhea???

I just thought it was from the allergy but it should've cleared up by now because it has been over a month of no dairy or soy.

So then I thought maybe she is allergic to more but she isn't fussy at all during the day or uncomfortable. Just the mucousy stools (and very bad eczema).

She also is gaining weight a little slower than she should be. She looks healthy though and is meeting all developmental milestones.

Last night she had a stool that had no poop in it, it was just entirely clear mucous.

She is also teething a lot right now so I know that can cause mucousy stools but this seems excessive to me... I'm not sure what to do/if I should be concerned.

We are seeing an allergy specialist soon. I want to take her off the medicine as well to see if that is causeing any of it because her reflux seems completely gone now.

Sorry for the incredibly long read. Any tips or suggestions would be so appreciated!!