I can't touch anything because i think i will get someone pregnant. can girls get pregnant from object that had semen on it?

Well...: My first question is why are you touching things that have semen on it? Just wash your hands. If there were semen on your hands and you placed it inside the vagina i suppose pregancy is possible.

No: not by touch but if that object comes in contact with your vagina, it is possible...

Address worry: You know from health class that you can't impregnante anyone with objects with semen on them. However, your concern about this is likely making your life more difficult than it needs to be at 19 years old. You may want to discuss your worry with someone, along with any other worries you may have. Once you get your concerns in perspective, you will likely feel less burdened and enjoy life more.

Anxiety: How you touching an object would get semen on it or impregnate a woman who touches it at some later date? I'm sure there are much deeper anxiety issues than just this concern which by the way would have been addressed in your high school health education classes. Please seek consultation with a qualified mental health specialist regarding your unreasonable sources of anxiety.