Selling some things and investing in Ethereum is a good idea?
I'm not sure if you are being serious or not. On the offchance you are being serious, then ask yourself this...
1) When are you looking to sell
2) Do you think the price will be higher THEN.
It's literally that simple.
For me, I'm looking to sell in about 10 years. I think even $2k Ethereum will be a good buy, when looking at the perspective of 10 years from now.
For that reason, I'm very comfortable buying. I pair that with the fact that I'm not buying in too hard too fast, so this makes it easier to swallow pullbacks like this.
That's my approach, find what you are comfortable with and do that.