Love?

I've had a few situations in my life where I thought I had been in love. Has there ever been a person who has effected you with just their presence? I have. So far in my life I have met two women that have had a physical effect on me when I am in their presence. I had a bad experience with the first woman; of course we were just juniors in high school at the time, and well high school girls tend to be very harsh. The other girl I just had a lot of trouble talking to. When we talked to each other, we would get very awkward and discuss things that I doubt either of us were interested in. I mean I remember running into this girl a few times outside of high school (this is a few months after it was over with), and the effect was pretty obvious. I could feel the effect throughout my nervous system. weak in the knees? No, try weak in the whole body. I felt like I was being strangled by an invisible force. I'll write more on this later, but I'd like some input and experiences.