I think you should wait. I don’t think you can get a second ITIN if the first one is not expired. The IRS would not have processed your 2018 tax return and paid your refund unless they first issued an ITIN. I don’t know why you didn’t get a letter last year, maybe it was lost in the mail. Is it possible that you used the wrong address on your tax return? You should use the address where you want to get mail from the IRS, which does not necessarily have to be the address where you live during the tax year.
