Please remove if inappropriate My LO's poop has trances of blood in his stool.. He is on total breastfeed.. What could be the reason..?

I went to the PD previously, she told us it's because of his gassy stomach that caused explosive poop which resulted in blood in stool. It could also be because of my diet as I took milk. I had removed fresh milk from my diet. I recently took back soya milk and had almond these few days. I gave him colic drop frequently and applied cream on his anal. There are one or two occasion which we did not apply the cream or miss the colic drop and that's when the blood stool happened.. Will the blood stain affect his stomach? Is it a serious condition?