Using the same speed test, I'm getting around half the speeds you are seeing, but there can be two or three people streaming video at the same time here without any really obvious problems or delays.
Whatever the speed test says, your actual speed for any site you want to look at on the net is dictated by the speed of the slowest part of the link to that site. That's been true ever since I started using the net over 20 years ago, but most of the time these days it's not a big issue.
That blue circle usually means that the video is "buffering" as gingejbee said, but it can also mean that there is a problem connecting to the site on which the video you are trying to watch is stored. That might mean that the site is extremely busy and isn't managing to stream the video to you quickly or that one of the links in the chain to that site is being dreadfully slow.
I don't use Facebook, so I have no idea if this is possible or not. You could try opening the video link in a new tab in your browser (try right clicking on it and select open in new tab) to see if that solves the problem, or if you can see the actual URL for the link, try copying it and pasting it into a new tab. If something like that works, the chances are it's some oddity with Facebook (or whatever other place you are using) rather than a problem at your end.