If you are stressing about being pregnant when you really arrant. Can the test come out positive?

My best friend Chela meet my other friend Rick. So they liked each other from the start so they went out. She lost her virginity to him. They been together for a year. Ever since then they had but only with each other. So one day they fooled around, and she didn't get her period in May nor in June. But ever since they had that one time she stressing. She think she is pregnant but i told her the more you think about it you will get the synonyms of being pregnant when you really not. But I read in a magazine that if you think about it a lot and if you take pregnancy test that it can come out positive. So i boughtt her a test she took it: it said that she is. But I truly think she is not. Thing is if her parents find out she is going to get kicked out the house. Rick said she can stay with him. But he is going to the army less then a year. I want her to stay with me, i doubt my parents will. Chela is like my sister I don't want to see her fail. Can someone give me advice?