Iphone 5s not backing up to icloud. It's been two days

Welcome to the Apple Community Alexis.

The first back up to iCloud may take some considerable time. Just how long isn't really possible to say without knowing how much is in your back up and your connection speed.

What many people don't realise is that upload speeds are often significantly less than download speeds, so for example a user may have a download speed of 40 Mbps, but only 1 Mbps for uploading. As a rough guide it will take around 2 ¼ hours to upload 1 GB of data at 1 Mbps.

The first thing to check would be your internet upload speed, you can do this at www.speedtest.net.

5.26 Mbps should be just fine.

Where did you check this, on your computer or on your phone.