Help with really bad constipation please!!! its freaking me out.?

i've been eating like normal and everything but suddenly my bms are really hard and its been going on about a week and a half . i dont know what to do!!! i tried a laxative that helps but it upsets my stomach too much i trried activia nothing gives! should i see a doc or what. and i've also been really gas i always have gas. and its all so sudden!