I know it seems like prices sometimes reverse direction as soon as you buy in but its not always the case. Id say you tend to remember the ones that reverse direction more than those that dont.

With regards to ETH, you realise its total market cap is closing in on bitcoins at a decent rate? That means any sensible investor is likely to sell their bitcoins soon and buy ETH which is only going to drive ETH up further.

If you want my advice, buy as much ETH as you can now and then just forget about it for a few weeks and check back later and see what its worth.