Three days ago I had oral sex with my boyfriend, and later the next day I began to get a stomach ache, and then a headache. Soon I was feeling light headed and dizzy so I went to lay down. The next morning I awoke to find my feet and hands extremely itchy. The itchiness got worse and it become more of a rash. I then got a massive fever and laid in bed all day freezing. At this point I got worried and researched it, and think I may have an STD, particularly syphilis. But since we only had oral sex, if it is an STD, wouldn't there be something wrong with my mouth or genitals, and does an STD act up after only a few days?