What is going on?

So I just stopped my bc on Monday and this was the first month my husband and I did not pull out during sex. I should have my last "bc period" and I started to bleed Thursday. One spot in the underwear maybe a teaspoon. Yesterday I used tampons and barely even a drop of blood all day. I normally have a light flow but I almost feel like I don't even have it. Anyone else have a period this light?