Suggest Treatment For Blood In Semen

I went for a vasectomy first week of June 2010. When I needed to go for the semen test 8 weeks later they told me there was pus cells in and they could not determine if the semen are still alive. Antibiotics were given (5 day course). Now when I have intercourse there is blood coming out? The doc said it might be antoher infection and wanted to give me stronger antibiotics. Never before the vasectomy was done was blood coming out - why now? What is the colour of semen suppose to be after a vasetomy? Do you have more libodo after vasectomy?