What Causes Pus In The Urine?

hi, i have a problem. my urination has pus(sometimes it s there and sometimes it s not) but the day before today, but the pus i ve dishcarged was big. I mean it came as pieces(3-4) not so so big ones but scary however.I visited a doctor a year and a half ago, but i didn t buy the medicins as am a student and can t afford such expenses and at the sametime I don t want to tell anybody(like parents) about it.Now, I m terrefied and so worried, because illness might have develolped more and more. Also, the last two times i ejaculated i felt a little pain.Today i ejaculated and the sperm\semen was browny.(note that I didn t ejaculate for a week or so) and in this period I am ejaculating 1-2 times a week.could this be the reason? should I ejaculate more often?(sorry for excessive use of that word). By the way, the white pus\substance comes after I urinate and I feel like it s a new wave of urine coming but it drops a white\yellowish substance.Also, it happens when while boweling . I found some one who have the same problem and describe what happens better. quoting him: Most recently when I go to toilet and try to press bowel movement, on the very first initial press before bowel comes out, I can see that sperm comes out thru my penis. It happens only once on each time I go to toilet. For instance say if I spend 5 minutes for bowel movement, it only occurs during first 10 seconds with first press to muscle. Any thoughts or suggestions, please? I do NOT have any sexually transmitted disease. It just happens automatically even w/o the penis being getting hard. Also you know, I m not trying to get it hard during bowel movement. So it happens automatically. Any help or thoughts will be appreciated. WWW.WWWW.WW Please note that am also sure I don t have any STDs because I ve never kissed, had intercourse, foreplay with any girl.except that one time when I inserted the back of toothbrush(cleaned it with soap) in my anus to find out what kind of pleasure girls get.Believe me they are sick ! and it s painful and not pleasant at all. am 23 years old male. I m afraid that neglecting this inflmation\infection( Idon t know what it s called) this long period(year and a half) might have caused a serious disease like prostate cancer or gland prostate & such horrible diseases.I ve ejaculated once again before an hour and sperm seems to be yellowish and there was no pain. thanks in advance.