Well, if you didn't pay the first and 2nd quarter yet, you've already got a late payment penalty for those two. So what you need to do is pay your 3rd quarter taxes *NOW*. So that you "catch up" everything with the 3rd quarter payment, you need to send the IRS at least 20% of your gross earnings for the 1st, 2nd and 3rd quarters. That will stop the accumulation of interest on your failure to pay for the first three quarters.
You can pay right now online at http://www.irs.gov/payments. Pay attention to the screens as you work it through, so that you CLEARLY identity this is a 1040-ES payment for tax year 2018, for the 3rd quarter. Again, that 3rd quarter payment needs to be at least 20% of your gross earnings for the entire year to date. Then your 4th quarter payment is due by Jan 15, 2019.
Since you never paid the 1st and 2nd quarters, I would recommend that for the 3rd quarter payment you make it 25% of your gross business income year to date, just to "cover" yourself with the late payment penalties that you know have been accumulating.
Now generally in the first year of business, you can get a waiver for the fines and penalties. But by law the IRS can not exclude the accumulated interest on any late payments. But generally the fines and penalties for late payment are so low that it's just not worth the paperwork.
