If you filed a tax return showing that you owe, then you don't get a refund. Your tax return is a document that calculates the amount of tax you owe (your tax liability) based on your income, deductions, dependents and credits. Then it compares your tax liability with your payments into the system, either estimated payments or withholding from wages. If your withholding is more than your tax liability, you get the difference as a refund. If your payments are less than your liability, you owe additional tax to the government.
While most people get a refund (because their paycheck withholding is more than their eventual tax) it is not guaranteed. Every tax return is different. If you owe additional tax for 2017 (because you did not have enough withheld from your pay) then you need to pay it ASAP. The IRS will charge you additional penalties and interest for every month you are late.
If you want a larger refund in the future you would need to change your W-4 at work to reduce your number of allowances you claim, that will result in lower take home pay with a higher refund at the end of the year. Although, there are so few pay periods left in 2018 that changing it now probably won't make much difference to your overall refund for 2018.
