When I started playing CSGO I got placed into MG1, after that I've ranked up a few times until I hit DMG. Valve recently changed up how ranking up works, so they made it harder to reach the upper ranks. With that many of the old ranks that you had were taken away. Like if you were LE you most probably would be down to DMG.
That happened to me. I ended up on DMG and played myself up to Legendary Eagle Master after that wave. But now I've deranked again and stuck back on Legendary Eagle. I'm slowly grinding myself upwards getting to Legendary Eagle Master with as of now - 214 competetive wins.