HTC One Trouble Charging

Hello, 

Over the last couple of days, my phone (HTC One) has been charging extremely slow, sometimes even losing power while charging. It hasn't fully charged itself in 3 days, and the last couple of times i have tried to charge it, the phone battery will either go up by only 2 or 3% in a couple hours, or it will drop in battery life even though the phone says that it is charging. I am using the original HTC cord and have tried computer USB and power outlets, still no better results. 

I am trying to avoid having to replace the phone, so any suggestions? 

Thank You