Is this a panic attack?

Sometimes i get so overwhelmed by certain emotions that i go into this weird freak out session and i don't know what it is. its only happened a couple of times, the first time was after i found out i had to do a ten minute presentation. i went home and i had started shaking and crying, and then my heart started beating really fast and i felt like i couldn't breathe. i didn't know what to do and i couldn't put anything into perspective i just felt like there was no hope and i was very scared. i just end up siting on the ground freaking out untill i feel better, which is usually like 10ish minutes later. then sometimes i get so angry that i lose control like that and i feel like there's just no hope at all, and i end up doing the same thing with the same symptioms i explained above. it happened again yesterday because i was upset about something and i started shaking and crying and i felt like i couldn't breathe and my heart was beating fast, all that. it also starts to happen sometimes when i feel like i cant breathe because i have asthma and it freaks me out. so are these panic attacks or am i just really upset?