I am self employed. This year I contributed to a SEP and rolled over my previous employer's 401k. Do I add both IRAs together as a contributions to an IRA for 2019?

No, your rollover is not considered a contribution so you will not enter it as a contribution.  You will enter the 1099-R received from the 401(k) sponsor that shows the rollover. 

Also, do not include your SEP contribution in the regular IRA contribution section of the program. You will enter this in the self-employed income and expense section of the program under Other Business Situations, and then Self-Employed Retirement Plans.

A rolled over 401K is not a contribution so you don't enter that amount as a contribution on your tax return. If you received a 1099-R for the rollover, you must enter it on your tax return and indicate how much of it was rolled over.