Am I in starvation mode?

Hi, okay, so recently I was totally stressed out because of school. I ate around 500 calories a day for four days. I felt sick when ever I ate. Anyway, I lost 1.5 pounds, and now I'm not stressed and very hungry, I am prone to weight gain. I worked very hard to lose the fifteen pounds I lost prior to this event, and would not like to gain it back. Anyway, am I in starvation mode? If, so how do I get out of it?

Symptoms: 
-Stomach hurts
-Very thirsty ( I normally drink about 10 cups of water a day, and today I drank about 8 or 9)
-I would have trouble focusing, if i had not taken my add meds.
I am 15, 5'5" and 131.5 pounds. I started as 133 pounds.I am still looking to lose about 10 pounds, but I want to do it safely, so could you please tell me how to safely get my body out of starvation mode without gaining weight, thanks?

During the FOUR days, I had to force my self to eat:
day one:
Grapes (1 cup) breakfast
Grapes (1 1/2 cups) lunch
Potatoes and green beans (250 cals) dinner
I think I ate one more thing, but I can't remember
Day two:
Grapes (1 cup)
Grapes (1.5 cups)
pasta type meal (150 cals) 
ice cream (35 cals)

Day three:
Banana plus .5 cup of blueberries
grapes and blueberries (1 cup) and a kashi peanut peanut butter granola bar (140 cals, 7 g protien, 5 g sugar, 17 g carbs)
kashi bar (140 cals)

Day four: 
coffee w/ a little bit of milk (50 cals)
half a med sized banana

Blueberries (.5 cup) and kasha bar (140 cals)

kashi bar (140 cals)

shrimp meal (150 cals)