Blood in baby’s poop

I’m gonna be THAT mom but I won’t post a pic yet. My EBF baby had blood in her diaper for the first time today - 5 months old tomorrow. It was bright red and little streaks here and there. She’s acting fine otherwise and eating fine. Do I need to call the pediatrician or would you wait it out?

I will say I’m kind of suspicious of a dairy allergy. I mostly avoided dairy the last 5 months because my nephew had a dairy allergy so I was scared my daughter would too. In the past two weeks I’ve had cheese and other forms of dairy that I have not had in the last 5 months. Just seems suspicious timing.