it definitely can be a result of lowering calories or even your nutritional status as a whole. even if a person's weight is normal, there are a lot of things that can affect your period.

it could be a concern because if you ever want children but it keeps being different due to your intake, you might want to readjust what you are doing so it doesn't cause fertility issues potentially in the future for you.

i would keep track of it and maybe try to add in a few more snacks if it keeps going like it is in the months following. and definitely tell your doctor and therapist if it continues.