The problem is that we should understand that a normal sexual desire is airways necessary to get an erection. If your desire is less you may be unable to get a good erection and also can have problems of early ejaculation. Your might also be experiencing difficulty in sleep and anxiety.
You need to get hormonal profiling done and if required a vascular quality assessment.
Next Steps
consult a sexologist and get investigations done
Health Tips
have a good sleep and follow antioxidant diet