Severe lower back pain since yesterday please help

I have an intense lower back pain that I have never felt before this. It starts very low in my back, almost my butt and radiates down my glutes and backs of my legs and stops right at the back of my knees. 
The pain started out feeling like constipation because it seriously started in my butt and sort of in my lady bits (just very low, pressure-y pain everywhere) but it's reached out to other places and hurts much more now. 
Nothing helps except sleeping (and I'm not one to take meds unless I can't even get out of bed). Standing doesn't help, laying down doesn't help, it's just a constant pain unless I'm unconscious.
I just finished my period te other day, so it's not from my period and it's now almost impossible for me to be pregnant.