Terrified and feeling alone. Referred for urgent ultrasound :-(

Hi all. 38F here in the UK. Just got back from the doctor. I’ve been having lower pelvic ache and lower back ache similar to period pain for the last couple of months, on and off. No change in my periods and the pain isn’t bad it’s just an ache similar to period pains. My periods have always been fairly heavy. Doctor today said she can feel something in my lower pelvic area in the middle, a lump I suppose, another doctor checked too and said the same thing. I’ve also woke up during the night a couple of times recently sweating even when I’m not hot. Not covered in sweat, just a little bit, but enough to slightly dampen my pillow. So now I’m petrified. I’ve been referred for an urgent ultrasound. I am crying as I’m so terrified and have serious health anxiety as it is. What could this be? It seems to be right low down in my pubic area (roughly lower than halfway between bellybutton and public bone). I’m absolutely terrified of C. Please help I’m in tears as I write this :-( has anyone else been in this situation and what it turned out to be? Appreciate you’re not doctors but I suppose I’m just looking for reassurance :-(