First, you have to know the total amount of depreciation already taken up to and including the 2018 depreciation. Without your 2018 tax file or a printout of same, it can be difficult to get.
One thing you might try is to go to https://www.irs.gov/individuals/get-transcript and see if you can pull a transcript of your 2018 return. The information you will need "might" be in a transcript. If you can't pull it up online, then have it mailed to you. The IRS will mail it to the address on your most recently filed tax return.
The fact it will take 4-5 days for you to get it in the mail is irrelevant at this point, since your 2019 tax return is already late.
