I was 17 when I got chlamydia for the first time. At the time, I was dating someone who one day before going down on me asked me "I don't mean to sound rude, but why does your crotch smell like this?" After pointing this out I simply thought that change in my discharge and odor, plus the slight itchiness and redness were symptoms of a coming yeast infection. Much later the person I was seeing got tested during a physical and let me know they had chlamydia. We had had sex without condoms a few times and never talked about getting tested together.
Chlamydia is a super common bacterial STI that can transmitted through oral and penetrative sex (butt and front (vagina) sex) without a barrier, and child birth.
Symptoms: lots of STI's share similar symptoms that make it difficult to figure out what is happening. It is also quite common to show no symptoms at all, so getting tested is the best way to know. Some symptoms are: burning while peeing, spotting between cycles, pain in lower abdomen, pain during or after penetrative sex, a change or increase in discharge.
Treatment: oral antibiotics. if left untreated it can lead to infertility in all humans, pelvic inflammatory disease, chronic pelvic pain, pregnancy outside the uterus (ectopic pregnancy)
Prevention: there are lots of options! getting tested (yourself and your sexual partner/s), completing antibiotic treatment, having sex with barriers, abstinence (if that's your flex), having sex again once the chlamydia is cleared (to prevent passing it between each other).