your five year exemption from days presenting counting would have expired in 2017. So for 2018 you would dual status --- till you reached the 183 days to pass the substantial presence test, you would be a non-resident alien and thereafter you would be a resident-alien for tax purposes. Thus you would require a 1040 filing and attach a 1040-NR for the first half of the year. Note that while you are a Non-resident alien, US will tax you only on US sourced income and thereafter ( i.e. as a resident alien for tax purposes) you would be taxed on your world income-- and eligible for any taxes paid to another administration/country on income form that source.
For the 2018, you can also request ( a note signed and dated ) to be treated as a resident-for tax purposes for the whole year and thus file only a 1040. This of course would mean that you would have to paperfile.
Does this help ?
