Help please!!

I had unprotected sex two cycles ago on the first day of my period. My cycles are very very regular and they're about 26-27 days long. Well, last time, my period came earlier (23-days cycle) and I had about three days of brown discharge BEFORE (which has never ever happened to me) getting a bleeding like a period but very very light and only lasted for 4 days (my periods usually last for 7 days, it's been that way for 8 years). I had sex again on this last period but it was protected. Should I take a test? I'm quite worried. Why are my periods so light and short?😥 I'm not on BC, just condom