COLON INTESTINES POOP QUESTION PLEASE ANSWER ME !!! HELP !!!?

what does it mean if i feel like i have to poop , not sure if i do or not , and when i sit on the toilet nothing comes out ? ive been this way since yesterday evening . i took two glasses of water with mirallax in them and ive only eaten two pieces of chicken since it started to happen . should i be worried ? is this normal ? do in need a docter ? is this dangerous ? whats wrong with me anything helps please has this happened to u or someone you know personally ? PLEASE HELP ME !!!