To much hype happened on ETF and after the approval happen maybe there's a lot of people cashing out their profits and that maybe the result.
But also come to read this article since this also have relevance regarding on your question and maybe you can learn something from this https://u.today/key-reason-behind-bitcoin-btc-price-crash also this https://u.today/massive-200000-bitcoin-btc-dump-expected-in-60-days-mt-gox-update
If this is really happening well we can really expect a dump to happen so maybe its time to follow those good updates happening since it can give us good ideas on what will be the next thing to happen in the market.