Whats wrong with me, dizzy, lightheaded, nauseous, hot???...?

Well today i was at work in my office and i was feeling ok when all of a sudden my heart started to beat fast, i got really dizzy and lightheaded and i was like omg what is going on so i started to freak and i got very hot and started to sweat all over and i quickly got up and went to the bathroom i felt dizzy walking there but i took deep breaths and cleaned sweat with damp towl and felt a bit better. the headache continued all day though. and this happened yesterday too. i also felt like my stomach was very tight and nauseous as well. then i felt very cold afterwards and was told that the office felt ok. idk wat is wrong should i go to doctors? wen i went to bathroom i decided to see if i wanted to poop but only gas came out no poop, i went later in the day and just a bit of stool came out...should i see a doctor? i am currently on doryx for acne and i had a protein shake for breakfast herbalife i think