Help!

My internet is working fine then out of the blue it starts trying to register the download and upload. I have reset everything multiply times unplugged and replugged back in. Then it starts flashing amber green trying to download firmware. It reset and took about 2 hours to finally connect. Now I have a super slow upload speed when download is fine. I had just received a brand new panoramic modem/router yesterday. And this is all very stressful when I am working from home. Can someone please tell me they can help me!