Mark to Market Returns turns Negative

At the beginning of 2018, my mark to market returns were around $15,000. However the recent downturn in the Singapore market erased all these returns. You can see the 'Total profit (mark to market)' entry is negative below:

Some causes of the recent downturn in the market could be due to Trump's trade war with China. And also the lackluster property market in Singapore with the introduction of more cooling measures by the government.

Fortunately, with dividends, my returns are still positive.

As my investment duration is ~30 years till retirement, it pays to stay invested in the market.

If I have more 'bullets', I will buy more now.