What’s happening?!?!

So I slept with someone new last week, and a few days later I started having minor minor pain when I urinate ( I wouldn’t call it burning) and then having chunky brown discharge “flaking” off my vagina and then tonight I had some blood in my underwear. I also have some constant pain in my spleen area.

I want to keep telling myself it’s just a bad UTI. But I’m terrified it’s Chlamydia.. I’ve never had an STD before.

Anyone have any insight before I drop an arm and a leg on a ER visit..?