Eliana,
I like that you change things up and experiment - that in and of itself is incredibly valuable.
The second thought is - track your data. If you have a day when you feel tired, check in on your calories. Try the next week at 1700 calories and see if you are as tired as at 1200. Look for trends and work from there. I'm sure you could've figured that out without my help, but you DID ask.
Keep us posted!