iPhone screen went black, can't hard reset?

I have an iPhone 5s. A lot of times my screen went black and basically shut down. The only way to fix this was to hard reset, hold home button and lock button at the same time and it would reset. Today it just happened again. My iPhone went black and it wouldn't work. Now I can't hard reset because my home button doesn't work so my screen is stuck black. I haven't backed up in a long time so I can't erase it. I tried charging it and it didn't work.

What do I do now?