Your technique in trading may not be effective for now what you did is trading without making any calculations and at the same time wrong timing. You should make some sort of research to learn how the market for ethereum work, also if you only monitor the price you could have seen that the is not good for you to sell and the most important thing is have a trust on your investment it may drop but always believe it can recover soon
Yeah, timing and techique are everything we need in trading. Without those skills your trade could be a big fail. I think the OP could use other timing and calcutions but find the good one to follow.
We need also to know about the coin, because if we do not know about the coin we have we didn't notice what really next happen on that coin if its going down or increase.