There are some simple exercises you can do to "un-pinch" the nerve and any midwife or physiotherapist should be able to teach you.
I can try to describe them, but not easy to write!!
Lie on your back on the floor - on a soft rug or duvet. Keeping your back straight and shoulders relaxed, bring your knees up towards your chest, hugging them as you do so. Never stretch or strain. Then lower them again, resting your feet on the floor.
Keep your knees bent throughout, so you don't strainn your back. Repeat twice more.
The do the same manoevre but pulling one knee up first 3 times, then the other.
Rest both feet back on the ground, knees still bent.
With me so far?
Now, keeping your shoulders and back as near to staying on the floor as possible, roll gently, from the waist, keeping your knees together, as if you were trying to place your right knee on the floor beside your left elbow. You wont get that far - I am just trying to describe the general direction.
Bring knees back to midline, then gently roll the other way. Finish back at the midline, pull knees up towards chest, and relax.
When getting up - from bed or examination couch at the clinic, never sit up straight from lying down. ALWAYS roll, keep knees together, place feet on floor and stand. If getting up from floor, roll to hands and knees first. then stand.
Keep knees together- never swing one leg off the bed, or out of the car - your pelvis will have loosened up and you risk hurting yourself.
Fold a duvet in half and lay it on your mattress to sleep on - that will help your back.
if my description doesn't make sense, ask to see physio.
Phew - I am exhausted now.