3 month old having BM issues...?

Hi - my son is 3 months old and for just over a month has been having a lot of green mucousy and sometimes frothy stool. The Docs kept telling me it was okay as he is solely breastfed but a Doc I saw recently was concerned, and now a bit of blood has shown up in it 3 times - twice it was just tiny flecks, once was a little mucousy dallop of it. I cut out cow's milk when he was around 3-4 weeks and now am also going to try cutting out soy. I know it could be a foremilk/hindmilk imbalance but I've also been trying to do 3-4 consecutive feedings per breast to try and help with that. We've begun submitting stool samples - the bacterial infection test came back negative and they are now testing it for a parasite. He has also been spitting up more and that as well as his stool have been smelling somewhat acidic. They said if it is acidic (being tested), that maybe he's missing an enzyme that aids in absorption in his intestines - not sure how serious that is. He was having fevers but those have seemed to ease up over the last few days - but, the green mucousy poop persists. All of this could also just be due to a virus which they just let run it's course. He is gaining weight fine, playing like a champ, smiling a lot and doesn't seem to be in any major pain. Has anyone had a similar experience or have any thoughts? I know I gave a lot of detail but the more the better right?! THANK YOU!!!!

My son's poo is acidic and green and mucousy when he teeths!