Some of the medications you have been taking so far have added to your misery. Stop everything and consult further for correct medication. You dont seem to be needing any more investigations and onle a very minimal treatment.
A discharge per urethra at the time of defecation could be urine, as you relax both anal and urethral sphincter when passing stools. Pressure with hard stools on the prostate may also result in some prostatic secretions coming out of urethra especially if you have some prostatic inflammation. Presence of pain in testicles may also indicate the latter. Although none of these could be serious, you need proper examination and necessary investigations. Consumption of corex, mentioned by you on a non-serious note, is, in fact, more worrying as it indicates addiction. You need proper psychiatric consultation for that.