How to get my sister to stop freaking out about being pregnant?

ok this is annonomous' friend again. my sis is STILL freaking out over being pregnant *she's not really pregant... she's just always like "omg what if I'm pregnant" if her period doesn't come the same time or something*. she gets her periods, she has never had sex *or even been naked with a guy* so no sperm could have got in her to get to the egg. so how am I going to tell her so she KNOWS that she's NOT pregnant?

any advice/suggestions would be nice... and if you're going to give mean comments... please don't yell at annonomus... because this is her friend *she let me use her name again since I don't have a comp and need advice on this*. ok? thanks

Just let her know what you told us- if no sperm has been near her- no guy has ever been naked with her- then there is no posible way that she is pregnant. Maybe she did do something sexual with a guy and is hiding it from you? She maybe COULD be pregnant for all you know- but thats her personal life.

well she's my sis and she's been honest with me *I know cause she's never had a boyfriend* and our parents NEVER allow guys to be alone with us just to prevent such things. I mean even when I tell her if no sperm has been near her she's ok. I tried talking to her tonight and think I found the problem. her a group of her girl friends were playing a game of truth or dare. well one of them decided to do a "group" dare where everyone did the dare. and they agreed. the dare was each one had to hump a pillow just for laughs. well I think she thinks by humping a pillow she had sex and there's a chance she's pregnant. I was like amber... there's NO possible way that can happen! your NOT pregnant! you need sperm to get you pregnant. and I think I might of got through to her cause she said thanks.. you made some sense I think.

so did I do good by telling her that?

You seriously should just buy her a bunch of pregnancy tests.(hey sisters got to bust on eachother sometimes right?)

Have her take a test if she still is worried... hopefully that will knock some sense into her and get it through to her that you cannot get pregnant by humping a pillow.

Make her watch the discovery channel or something. LOL

ok first off this is annonomus now...
lol that's funny
I mean my friend always tells me what her sis is doing and I'm like omg are you serious?! lol