Long Distance Pregnancy Intuition?

Hi,

I'm new here.  About 5 weeks ago (around 9/22/12), literally 30 minutes after my husband and I DTD I was convinced I was pregnant. We're definitely not TTC right now, but it's possible because we only use the pull-out method (has worked for us for the past 5 years). The next two days afterwards, I had super painful cramps, which is unusual for me because I never, ever cramp. A week later I had brown spotting that lasted for 3 days, then a light-moderate period for 2 days and then brown spotting again. Usually my periods are very heavy and then taper off after 4-5 days, so this was unusual. This brown period came a week earlier than I was expecting it also. 

Since my period was so weird, I took a pregnancy test, and it was negative. So I just chocked everything up to being a funky period and went back to normal life. I haven't noticed any obvious "symptoms" since then.

Just last night, my sister texted me out of the blue and asked me if I was pregnant. I told her I definitely was not, and she knows we're not TTC. Still, she said she "had a feeling" that I was pregnant. I have no idea why since we're a six-hour drive apart and I haven't seen her since early Sept. 

My question is - Is there any such thing as long-distance pregnancy intuition? I haven't taken another pregnancy test since the first negative and I really haven't thought about it since then. Kind of freaks me out though... Anyone have any similar experiences? Think she might be right?