Spotting while on th pill

I’ve been taking the pill for about 5 months , on the 28th of July I had sex we used a condom and i took my pills on time.

So yesterday and today I’ve been having spotting is more like cervical mucus with a string of blood, is this normal? Have any of you experienced this while taking the pill?

In addition that this past days I’ve been very stressed and anxious 😔