Baby aerobics in my tummy??

Last night, after I woke up at some ungodly hour to go for a wee (again... isn't that supposed to be easing up now I'm in the second trimester?!) I am SURE I felt little bean having a good old wriggle down there... I lay there and it really felt like he was kicking? The only way I can describe it is similar to how your pulse feels in your chest, only totally irregular and in your abdomen. Of course I could be completely mistaken, maybe it was wind... problem is, every time I think I can feel something, it's always in bed at night, so I close my eyes... concentrate.... and fall asleep! Doh!! Oh well I'm sure as he gets bigger ill be able to feel kicks for definite. At the moment it's all hopeful speculation!