Help please 😬

So I know this is the typical post but I am genuinely worried 😩, so I had sex on day 20 of my cycle and ever since about 4 days after, I've had a weird light brown watery discharge, what could this be??  Its been going on for 2-3 days now.. It's not the beginning of my period either cause it looks different and I've never had this before .... please help 😅