Low back pain, numbness inside both lower legs.. numbness when sitting in butt, gets better when i stand. i always have gad which think makes me worse?

MRI or EMG: Would see your doctor for a possible MRI and emg. Anxiety can certainly exacerbate symptoms. Depending on results, would try to treat medically.

PInched Nerve: The sciatic nerve is not the cause of the pain source, it is the result of an irritated nerve typically in the lumbar spine (low back) which are caused by herniated disks, spinal stenosis or degenerative disc disease requiring further evaluation by a spine specialist. Other possibilities include spondylolisthesis in which obtaining a a flexion/extension x-rays and MRI can help to evaluate this.