whales are collecting your profits. you have to invest at a low price. the question is: what is a low price?

There is something I can’t understand or something I’m doing wrong. I want someone to explain it to me or make me understand. For example, yesterday I had $6 and today it is $4. Most of the coins are the same amount I bought them for, but the amount is decreasing. How? 🙇🏼‍♂️