Advice please

Little bit of advice needed please, I’m 19 years old and have been on the pill since November last year.

I take my pill Every day and have not missed one , my last period was 1st - 7th October, I’ve had sex yesterday, last Thursday and then 27th September. Yesterday I had slight blood after sex but Didn’t think anything of it. However later last night (4/5 hours later ) I had more dark brown discharge then it’s continued into today , it’s not a lot but enough to worry me.

Any ideas on what this could be ? My friend told me I should take a test but I don’t know if it’s necessary or not.

So any advice on what this could be ? And Should I take a test ?

I’m worried and it could be nothing but just thought I’d ask before I try to get into the doctors🙂

Many thanks in advance