Yes, you are a resident alien for all of 2018. Assuming you hadn’t been an “exempt individual” before 2013, you would have been an “exempt individual” (exempt from the Substantial Presence Test) for all your days on F1 status in 2013, 2014, 2015, 2016, and 2017. For 2018, you would not be an “exempt individual” for any of your days in F1 status, since you have been an “exempt individual” for some part of 5 previous calendar years. (That’s unless you want to claim “Closer Connection to a Foreign Country” to be still an “exempt individual” after 5 years.) Therefore, all your days in F1 status in 2018 count in the Substantial Presence Test, and you have enough days of presence in 2018 to pass the test, and be a resident alien for 2018.
As a resident alien, you would use Form 1040 to file your federal tax return.
