Can u get pregnant from using toilet paper in a public restroom like if someone who had semen on their hands touched the toilet paper that I wiped w/?

NO!!!! You should write sci-fi novels. Picture it : alien from planet Zorbia crashes saucer in construction site next to porta-john; it looks like a fertility capsule from home;uses it to deposit alien semen into the sacred white bowl; wipes tentacles with toilet paper; homeless woman uses it later; gives birth 45 minutes later to what she thinks is an octopus;discusses with therapist at shelter, etc etc.
No. The odds of that scenario are extremely unlikely. Once semen has dried the sperm are not viable, meaning that the sperm cannot cause pregnancy. I hope this helps.