Confused. Need opinions.

Ok on New Years my brother in law and his girl friend came over and they all got drunk while I drank my sparkling juice lol. I was up peepin all night like every night lol and I don't flush at night to avoid waking up my kids. The next morning I woke up to a cup of pee on my counter so I woke them up and asked them about it. She said it was for a pregnancy test so she dipped the stick and it came up positive, VERY positive. Next morning I surprised her with another one she took one and it was negative. She said she must have taken it wrong, I didn't know it was possible to take one wrong. Three weeks went by she continued to say she was pregnant and started takin prenatals the whole 9 yards she had to go to the hospital for pain and they told her she wasn't pregnant her HCG was 2 and she still says she is pregnant that her levels just weren't high enough yet cause she KNOWS she is pregnant her body just does that the hormone just doesn't show up it did that with her other 4 kids too. Has anyone ever heard of anything like this? Part of me thinks she is trying to trap my brother in law cause he is super excited it's his first child. Am I terrible for wondering if she used my pee from the toilet in that cup on the first test, no one could be that crazy right?