I Feel Like To Need To Urinate And Poo And

I feel like to need to urinate and poo and can't do much of either. When I urinate I get very little out and it burns & hurts a lot. At the same time, I feel like I need to poo, quite uncomfortable, and when I try, I get very little or nothing out. If I lie down, the feeling that I need to poo goes away or is much less uncomfortable.
I had this a couple of months ago, starte, got quite intense and ended in 2 days. I went to a clinic when it was almost gone and they gave me a week of antibiotics. This morning, it's starting up again.
What do I do?