Do i have thalassophobia?

i dont know if im just afraid of the ocean or i have a phobia of it. i was on an app on my ipod and there was an ocean but i didnt know it was there so i was walking in the game and suddenly i was under water in the ocean and even though it was clear blue (no fish, no coral, no sea plants) i closed my eyes, hit the home button, and turned of my ipod. i could feel my heart thumping fast but not too fast and it was beating like that only for like 3 seconds. and if i see an ocean in a video or something i get scared and turn it off. when im in a real ocean i never go under with goggles because i dont want to open my eyes and see anything under the water. im really scared of the idea of the ocean getting deeper and darker and colder and when ur in the middle of the ocean its like endless space and things can just sneak up behind u. when im swimming in the ocean, if i cant touch the ocean floor when im on my tippy toes i wont go any farther. so is this a simple fear or thalassophobia?