Haven't been on here in a long time, which is great, but I'm in a bit of a panic state again.

Sorry if this is too much info, but I'm concerned about the colour of my poo
It's a darkish colour but it has a very obvious tinge of red in it. Today is the 3rd day it's been like this.
My daughter did bake a cake on Saturday, it was one of those mixes in a box you add egg and milk/water to. I had a rather large slice on Saturday and my bowel movement was normal on Sunday. Had another slice Sunday and bowel movement was red on Monday. I usually have 1 bm a day, and it has been like that on Tuesday and Wed as well.
The reason I'm mentioning the cake was I thought at first maybe that was causing it. It was called a Red Velvet Cake. Even though my bm was fine on Sunday, after having cake on Saturday. I had no cake yesterday so I thought I would be back to normal today, but no.
And when I say red, it's not blood. It's the colour of the whole thing, if you get my meaning.

I don't even know if this is a sign of anything serious. I've obviously not googled it in the past, and it's something I'm thankfully able to control nowadays.

Has anyone any thoughts on it? If it was the cake, should I have been normal today? And why wasn't it reddish on Sunday after I ate cake on Saturday?