What Causes Severe Pain In Lower Back Along With Numbness In Arm?

I am experiencing severe pain in my lower back and around my kidney on the right side. I developed sciatica problems on my left side in 2011 and never really had any treatment for it besides pain medication. I currently take 800 mg tabs of Gabapentin, 4 times a day (usually every 4-5 hours in between doses). That dosage would take most of the edge off, but I ve never been pain-free with this medication. In the last 2 weeks alone, the pain has been more severe and the medication is no longer working. I ve also noticed that I have numbness in my entire left arm and some on my right. What can I immediately take for pain or should I see my doctor or emergency room? It s been unbearable as of last night and all of today. I also have Type 2 Diabetes and take 60 units of Insulin Glargine (Lantus) twice a day and 35 units of Novolog before meals. Please advise.