The only reason you would file a tax return, would be if any taxes were withheld from your pay in 2018, so it would all be refunded to you. If your total earnings in 2018 are *LESS* than $12,000 *AND* no taxes are withheld, you have no need or requirement to file a tax return.
Since you have a child, I will point out that it would "appear" your child and *MAYBE* you can be claimed as a dependent on someone else's tax return. There's no way you could support yourself on only $3250 for an entire year, and you definitely did not support your child for the entire year, or for even six months.
What are you other sources of income? Disability? Social Security Survivor Benefits? Unemployment?
You do not need to respond if you don't care to discuss your situation in this public forum.
Yes, you can sill file a tax return for 2018 and you should do so. Sounds like you may be entitled to the Earned Income Tax Credit and possibly the Child Tax Credit. Both of these credits are refundable, so even if you had no withholding on your W-2 you could still get money back when you file your 2018 tax return.
Review the following information provided by the IRS on these topics:
I hope this information helps you.