I can't properly step on my left foot lately. Or when I bend down to p…

I can't properly step on my left foot lately. Or when I bend down to put on shoes, there's such pain It shoots into my left buttock. I walk normally on the street, then limp. But it all starts because of how suddenly it hurts. I have to slowly lean or lift my leg, otherwise it's wild pain. I don't know what the cause is. Everything was fine until one day this pain appeared. What should I do now? I don't know. Seems like I pinched the sciatic nerve. ?