I don’t know how to stop undereating.

I was put on a 1,600 calorie but with my daily activity level I decided to go for a 1,400 calorie diet instead. But, I don’t even know what I’m doing. I know I’m undereating but I don’t know how 1,400 looks like. So I just eat small and healthy but it makes my head hurt all day. Today I ate:

Apple and avocado on whole wheat toast.

Salmon and spinach and cherry tomatoes.

Rice cracker with almond butter.

Two whole wheat tortillas with beans and avocado.

I had to drink a glass of almond milk for my headache.

I really want to reach my goal to lose weight for September. And I know 1,400 is the way to go. My nutritionist put me on that 1,600 diet thinking I do more activity but I calculated my TDEE and it’s too much. I don’t want to undereat because I don’t want to feel bad or faint but I also don’t want to eat my maintenance calories which are just merely 300 calories away. I want to lose the weight.

I don’t know how to stop undereating.