I had the same problem with a pattern panel.
The others have given great advice, markers and looking ahead to see if you recognise one of the stitches, find it in the pattern and count backwards to see what stitch to start the row on.
If you really can’t work it out on your project (I was 3 days at this doing the math to try to work out which stitch to start on) then I suggest starting a swatch of the diamond shape and as you knit it really mindfully LOOK at what each stitch does and how it effects the pattern and builds on previous rows.
I had quite happily and blindly followed my given pattern and had no clue what was sitting in top of what. I had to learn how to read the stitches of that particular lace. A swatch (and markers) and paying heaps of attention to the stitches may help you figure out where you are up to on your project.
Good luck!