you're going to need 2 years of tax returns showing your self employment income.
since you made this switch mid-year, 2017 earnings as shown on your taxes might be too small. so you might not be able to buy until after your 2018 and 2019 taxes are filed. at least, not without a co-signer. There's no point shopping this around to other banks. The only exception might be if your self-employment is exactly the same career as your W2 job. if that is the case, go check with a mortgage broker to see if they know of anywhere that would accept that.
the last thing to note, for later, is that once you start showing rental income in your taxes, you can use that to qualify for future mortgages/HELOCs.