MSPI?

Sara • Wife, Mama, Sister, Daughter, APRN
My daughter is 15 weeks old, taking only breast milk (breast and bottle). She occasionally will have some reflux symptoms, but is overall a very happy baby!  She does commonly cry after she eats, but only until she burps and then she is perfectly fine.
Last week she had some orange/red tinted mucous in just one of her dirty diapers, which worried me, but she had zero change in behavior and was eating the same as usual.  Today, she had two more "bloody" stools, but her last disper was normal?!!
Pediatrician thinks MSPI is possible, anybody have any insight to this? Is it strange that some stools would be bloody, while others are normal? 
After Lots of research, she also occasionally does become congested after she eats, and has a little rash/dry skin on her face that comes and goes (More MSPI symptoms). Again, symptoms seem to come and go - which seems strange for a milk intolerance. 
I'm totally willing to cut my dairy, but I think I'll need to supplement with some formula.  She hasn't had formula yet, so I'm nervous to do that!
Any insight would be super helpful, I hate the thought that she may be uncomfortable - even if she doesn't act like it!! 
Thanks mamas!! 💕