It's sort of a glitch. I gained 5,000 followers in one month (https://medium.com/the-pub/well-i-am-a-big-boy-now-i-just-reached-10-000-followers-ab878b5db977#96e1-b98fca8f8deb)

Regarding the boost, try New Writers Welcome as I mentioned. They specialize in first time boosts :)