So i just got fingered in the butt for the first time today, and since then, i've had a stomach ache and there is some slight bleeding when i poop. also i've had the feeling of needing to poop all day even though i don't need to. should i be woried?

Yes: It's not safe, as one's anus is not designed for repeated in/out, in/out of fingers, penises, etc... Like in any big city, some streets are one-way and some streets are two-way. A vagina is created or evolved to be a two-way street (penis in, baby out). The gastrointestinal tract is designed to be one-way, with an opening on each end. Food goes in the mouth, and the brown stuff goes out the butt.