my friend thinks she is pregnant

Okay so I had a friend text me the other night thinking she was pregnant and her doctor said it was gaulstones. However, she's late on her period and started spotting this morning and it was just a little bit according to her. She also said her boobs are killing her (around her nipples and on the side) she said she hasn't had any cramping just her stomach is sore to the touch? Does anyone else think she could be pregnant or is she just stressing and her period is delayed, or could gaulstones delay a period? Help please. She took 4 tests. 3 were invalid and one was negative.