Thanks for your query.Based on the facts that you have posted it appears that you have Erectile Dysfunction
due to Diabetes
.Is your diabetes under control ?
Please consult qualified Urologist
for clinical examination. You need to undergo detailed evaluation t by doing some tests investigation and radiological studies before starting any treatment.
In the mean while you can take Tab Phospo Diesterase Inhibitors like Sildenafil(Viagra)
See your family Physician for dosage and prescription of the drug.