I'm not sure what you're reading, but protected oral and intercourse is very low risk.
There is a small risk for syphilis (uncommon in developed countries like the US, Canada, UK, countries in Europe, etc. - I wouldn't even worry about it), herpes and HPV. Those are spread by skin to skin contact, and condoms don't protect all of your skin, but do offer significant protection.
You are not at risk for gonorrhea, chlamydia, HIV, hep B, etc.
Try not to freak out. Your chances are very low from a one-time protected encounter.