So im 5 months and 3 weeks pregnant and ?

i ate today some cereal in the morning and after that i was doing hw and i had a head ache but it was weird because in a way i was still hungry so i got some pop tart and after i ate the pop tart theheadeache went away... know in the after noon i ate a sandwhich and sum chips... i was still hungry so i ate like 5 cookies after that i felt like my heart or pulse whatever it was started beatean faster and i felt short on breath.. so im a lil worried is this bad ??? does anyone have an idea what might be going on i know you guys are not doctors but atleast do you have nay ideas ?? has it happen to naybody ?