Detecting sexual tension?

I get this feeling that me and this girl have this strange tension towards each other. We don't talk much, because we are so awkward with each other. She's shy and I'm shy. When we pass each other we just look into our eyes but then she breaks it and looks at my chest? We laugh together, and when we talk there seems just to be something in the air that I just can't explain, but usually we don't talk a great deal because it gets awkward for some reason. We have known each other for few years and went through a phase where we flirted a lot, and joked with each other, but we didn't see each other for a few months, and the tension has changed, more from her I'd say. Could this all be in my head? When we pass or talk to each other I get a funny feeling inside!
Detecting sexual tension?
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