Hi Sara,
Great article! Whenever you feel a certain way after eating something, listen to your body. Your body knows what's good for you to eat and what's not.
Your mind may want you to be vegan, but your body says otherwise. This seems to be creating a conflict within you, which unfortunately I don't know how you could solve it.
The best thing I can think of is try justifying to yourself why listening to your body is beneficial when you eat. You need the proper fuel to function at your best! You wouldn't put regular gas in a fancy sports car!