Thanks for your query,based on the facts that you have posted it appears that you have not mentioned any thin about your sexual history in your query whether you had any unprotected sex before getting discharge from penis .
Please consult qualified Urologist
or specialist in sexual medicine for clinical examination and get following basic tests done to confirm the diagnosis.
1) Routine Urine test and culture.
2) Swab test and culture of a urethral discharge .
3) basic screening tests for STI.
Further treatment will depend upon the results of these tests and final diagnosis,
In the mean while you can start taking Erythromycin