Almost fainted a while ago...

Since this morning, I had eaten: one english muffin with one tablespoon of natural peanut butter, one small pear, and for lunch 125g pink salmon(boiled), 100kcal green beans and 4-5 cherry tomatoes. that was about 650 kcal in total.

 I went to ballet class about an hour after lunch, and I started getting dizzy,turned all white and was seeing all black while doing an exercice at the bar...I stopped and started in 5 minutes and then it was the same again.

 I dont know why this happened, i'm not tired and i eat well(1500kcal a day, every day). What could be the cause?

 I was feeling kinda dizyy last week during ballet class as well, but not at this level. I'm back home and i"m feeling just fine now. I must admit it kinda scared me though.

You're probably burning more than 300 extra calories at ballet.

Meaning that puts your net calorie intake below 1200 calories.  Your body may have been okay with this at first, but it's starting to take a toll.

I'd recommend upping your intake to 1700 a day and see if they dizzyness goes away (give it a few days).

I'm not in very good shape, I know if my heart rate gets up too high, I get close to fainting in some of my gym classes.

For today I would have eaten about 1800 really. 2 hours of ballet is about 500 burned calories. But I was planning on eating them after class( I hate going to class on a full stomach). Should i have a bigger breakfast? Is it important to eat them before exercising? I'm so full with my english muffin and peanut butter!

your very active. you not only need to take into account the calories that you burned today, but that you have more lean body mass which burns calories in &of itself. i suggest you eat more. experiment with the numbers. go up to 1600, see how you feel, if not better than try 1700, &so on.

I like to eat a protein bar or a veggie burger (just the patti) about an hour before my martial arts classes so that I have enough fuel to make it all the way through.

If you don't want to eat right before your class (understandable) eat more for breakfast and have a morning top-up snack on class days so you're not running on empty. Your body needs energy to DO the class, not so much afterwards.

You should probably eat a little more before class, or it may be something else, a change in hormones can cause that too  . . .  you should talk to your doctor.