Dear greg1post, KNOWLDGE IS A GOOD THING BUT INCOMPLETE KNOWLEDGE IS DISASTROUS...........
there is nothing like that dopamine
and oxytocine are responsible for your sexual desire if you have doubt about your chemicals responsible for sexual attraction are not well , get done your serum testesterone levels both total and free checked. either you are much stressed in these days hence feeling low sex appeal within you stress is a big sex drive killer. hence get done the above mentioned tests and consult a sexologist
who can evaluate you mentally physically and psychologically don't make assumptions it will increase your stress level seek help, consult the Doc. and you will satisfactory answer.