Rigevidon and unusual withdrawal bleed

[Solef_18_03]

I've been on microgynon/rigevidon for nearly a year now and I've just had a really light period with only really faint dark bleeding with occasional stringy/gloopy clots. I have been stressed that I may be pregnant but I have been worrying about nothing because I was on birth control and we didn't have penetrative sex. After having taken like 7 pregnancy tests up to 10/11 weeks they have all come back negative and aside from bloating I've had 0 symptoms. Is it normal to have this sort of withdrawal bleed and could stress be causing this?