PRE period smell

I was treated for BV two-three weeks ago and according to Glow im 5 days late but today I was peeing half asleep and my SO came in and said, "oh is your period finally on? I wiped and no blood...no spotting. I asked him "how you figure that my period was on" and he said, "because I smell a smidge of blood". I didn't catch the smell at first but its very light and sweet but it definitely smells like blood. I dont think im pregnant, I have heightened symptoms of PMS this month: low back pain, mood and appetite swings, exhausted, 8 out of 10 for general discomfort. just want to know if any woman can smell blood before their period arrives. Does anyone know what this is.