Since you are interested in Bitcoin investment, your current Bitcoin amount may be small, but it will eventually grow if you continue to accumulate Bitcoins as much as you can.
OP only bought around 15$ worth of bitcoin the first time. The coin's value will have to go up to $44.000 for him to double his money. Even if/when it does, he will only profit around $15 on that trade. I don't know where OP lives, but in most parts of the world, you can't get much done with $15 in your pockets. It's good to start somewhere, but one soon realizes that small investments like that aren't worth it.