Disorientation. Nothing is where it should be. I have knitted patterns written for dpn on circs and used markers to mark the end of each set of stitches that would have been on a separate needle. What pattern are you using? The 'last 3 sts on the needle' would be, I think, the last of the heel stitches on your circ. If you can sort out in your head which stitches are where in relation to what you're used to, I think it will make sense. Maybe because I knew you were doing top down socks in your other threads, I knew what you meant in the title. You can edit it if you want to. You might run down a pattern written for circs for comparison. The numbers of stitches might be different but the way to do it would be the same.
I should never overestimate my basic arithmetic skills.