What is wrong with me?

Ever since last summer... if i see something on tv [or see anything anywhere] it reminds me of my past-it gives me a flashback. I can't breathe through the 'flashback' it hurts. i feel sick. i feel dizzy. no one around me can talk while its going on. it makes me tired. i've told my parents many times. they haven't done anything. when 6th grade started... it went away. Now... it started again. it happens a lot i don't like it. help? please? thxx