Hi I Have A Constant Heavy Pressure Inside Like I

Hi
I have a constant heavy pressure inside like I need to urinate but when I go there's not a lot there. I also have a heavy feeling in my rectum. I have had major previous bowel surgery as I had laser surgery for endometriosis but unfortunately it went wrong and I had to have bowel reconstruction and a rectum made. (Had to have a colostomy then an ileostomy during the process which was reversed in 2002. The nerves to my bladder were also damaged and I was unable to urinate but over the years this has improved although I've never regained full sensation. Over the past year this heavy feeling has got worse and certainly over the last month or so and when I sit down I can feel a pressure in my rectum. . sometimes it feels as though my whole lower half has gone into a spasm and I need to urinate and open my bowels but nothing happens. Any idea what this could be as it's driving me crazy