STD testing. Is it worth it or am I just a hypochondriac?

Alright, so I am a 21year old female and Ill admit I am a moderate to extreme hypochondriac. Or maybe its just OCD. I have had 4 sexual partners, 2 of which I know were clean and the other 2 I have no idea. Anyways back in October I had unprotected sex with this guy a few times and about a month or so later I developed a huge body rash and I was CONVINCED it was the acute HIV rash. So I waited a while until I could be tested and I was negative for both HIV as well as Hepatitis. The tests were kinda expensive because here in California, or at least my town, they no longer offer free STD testing. I kinda felt like it was a waste and everybody was telling me I didn't have HIV and they were right. Well then a few months ago I got another rash on my back and I decided it had to be sacral herpes. I went to a dermatologist who said it did not look like any kind of STD but she took a sample of the rash to be sent off for a biopsy and I made her write on the lab sheet to test it for herpes. It came back negative and she concluded it was just an allergic reaction. Well since then I have not had sex (last time was almost 4 months ago). The past few days I have noticed my vaginal skin is more red and dry, and just slightly itchy. I fear it may be a mild herpes outbreak. I have no blisters or sores so I am unsure if I should get a test done because I read that blood tests for herpes are not always accurate and since I don't have a sore to be tested idk what I should do. I don't want to waste more money that i don't even have if the test is just gonna come back negative like all the other tests did. Am I just freaking out about nothing?? I just got tested for chlamydia and gonorrhea like 2 weeks ago for my annual and i was clean and the doc said i looked healthy down there. What should I do??