if I have to stop in the middle of something I find it hard to remember where I left off any tricks to solve that?

Do not worry too muck; lots of people have a strong intelligence but shaky memory.
It is the absent minded professor syndrome. There are worse things.

Bookmark if reading a book.
Save page if using computer.
Use stick-on note if a physical task.

Also, wake up a bit, treat the job as more important and notice current situation
maybe even say out loud or to friend what the next part should be.

Good luck.

Use a light pencil mark in the margin of where you left off.