Good morning Kassie

The added hunger is probably from the oatmeal you had this morning. Perfectly natural, as I sometimes get the same thing Also means you had a good workout You might try adding an after workout snack within an hour, like an apple with peanut butter, or celery and cream cheese. I found that also helps cut the hunger down a bit. Plus it helps the muscles recover faster.

Do you stretch? You might try adding in some stretching for the lower back area or ask your trainer for some exercises to strenghten the lower back area. I have a really bad lower back from a bike wreck I had in 1987. Literally tore my lower back all to heck. I have always had problems after that. I do lower back stretches before I get on the treadmill so it doesn't tighten up on me while walking/running.

Really happy you are doing well on your routine so far Keep after it.