How long should I wait between pregnancy tests?

Amanda

The top test was 9dpo around 3 pm (had nausea 9dpo and thought I felt implantation cramping on 7dpo) took another one this morning (bottom 10dpo) around 6:30am. I'm super paranoid because I had a chemical 2 months ago and my line doesn't seem much darker with FMU. Did I test too soon? The lines look about the same to me but I'm having a hard time telling if the bottom one is lighter/darker than the top.