Heart Health Cardiac Rehabilitation

hi i used to take diet pills about 5 years ago. totally quit taking any form of diet pills, and caffeine for 5 years. ever since then ive had on and off chest pain. unfortuantley i also used to be a smoker, which i just recebtly quit. And i drink maybe 1 glass a wine a couple nites a week. my dog had passed a month ago and ive been really sad over it. i am getting over it though, and it just seems that right when i was getting over it i started to feel really terrible. The past 2 weeks ive felt my chest pain more frequently. massaging my back helps. Ive also had some trouble breathing, feeling like i have to tell my self to breath through my nose. This past tues is when the troubke started. i was in class not thinking about much and i got really dizzy, had chest pain, and felt like i couldnt breathe. i left class and went home right away and slept. on wed i went to class and was feeling the same symtoms but this time they were worse. i had one taquito and immediatley knew something was worng. i just had lots of chest pain, and had trouble breathing. i went to the docs and they said i had a heart rate of about 1140-150. got in aambulence, they did ekg, xray, blood tests. i was at the ER all day. at the end of the day they said everything was normal, and it was all anxiety. i was so afraid to have a heat attack. is this really just anxiety. i do get anxious about a lot of things, even small things all the time, but this one hurt so much. they gave me some med i think called avaprom. the doc before i went to ER said i might have a heart condition. im confused i always feel so sick. my heart is still hurting right now, but its ok. is this just anxiety. i went to the docs 30 times last year for stomach aches, headaches. i just dont want to go to docs anymore, they jus keep sayin its anxiety. please help me, im really scared, im only 23 and have all these weird things ahppening to me.