If we look at Nasdaq, we can see that this index has broken below its uptrend line (at 7700) as well as its 200-day EMA line (at 7450). It has been a few days since the breakdown occurred - which may confirm the end of the uptrend. See Chart 3. This could mean that Nasdaq index may move sideways like what it did from July 2015 to November 2016. See Chart 4.
Chart 3: Nasdaq's daily chart as at Oct 15, 2018_9.45am (Source: Stockcharts.com)
Chart 4: Nasdaq's weekly chart as at Oct 15, 2018_9.45am (Source: Stockcharts.com)
In the above scenario, I am assuming that sideways movement would follow after the end of an uptrend. That's a mild assumption. The bearish assumption would be for a market that has peaked, to go into a downtrend. At this moment, it is too early to call to make that call because we are not entirely sure the long-term uptrend is over yet. So, let's fasten the seat belt for we may have a bumpy ride ahead.