Hi I'm 22 Male And Have A Gf I Have

Hi I'm 22 male and have a Gf I have sex with usually daily or every other day sometimes... Well about a week ago or two I noticed when I started going to the bathroom it was hurting me to pee and it still does it feels like if I put to much pressure peeing it's gonna hurt worse and my urine smells strong I don't know what's been wrong with me and also feels like my male part don't work as good as it use to since I been developing these problems and also my right side lower by my stomach and been hurting and sharp pains sometimes I'm scared to go to a doctor I don't know what I should do please give me your input... Thank you