Girl lying about pregnancy?

There' this girl i met , she was very pretty and nice. We got along pretty well and became good friends but she would continously bring up how she missed her ex. She would text me about it and put multiple sad quotes on her facebook. Though she no longer dated him, she said they had sex often still. After talking for a few months she invited me over. Being a guy i saw it as a great oppertunity. Being the extra protective type i peed at home hoping to rid myself of any sperm possibly in my precum. Eventually i showed up at her house and we had sex. I used a condom and even pulled out before i came. After that i drove home and everything was great, but as time passed we slowly stopped talking. After about 2 weeks she texts me asking why we no longer talk, i felt bad and we had a small conversation. But the next day she texts me saying she's a week late. I continued to tell her that theres no way since no sperm touched her, but she would continously say that she thinks she still could be and anything is possible. Well eventually she took a test and sent me a picture, it was 1 line with another shadowy grey line. She claimed it probably meant positive but after doing research i feel theres a high chance its an evaporation line. Well we talked and she says she will take care of it but she keeps bringing it up that she will take care of it like she wants credit. Well soon after she texts me asking me to come over to her house again, but i refuse because of the situation and how stressful it is. She keeps saying it shouldnt matter but it does matter atleast for me. Please tell me your thoughts and if you think she may be tricking me for attention?