My breast pump is one of those small portable pumps, it’s a single, it’s a Mipump - First Years http://www.1stbabyshop.co.uk/uploaded/products/big/ZZZZZZZZZZ_96115_do.jpg like this one in the picture. Anyhow, this morning I woke up before baby, awfully full, and had to pump to relieve some pressure. The pump started normally, so it sounded and then all the sudden it started sucking milk down the air tube and into the pump itself! I stopped it immediately, disconnected the tube and blew the excess milk out of it, the I shook the pump a few times and some milk came pouring out, but I can still hear liquid in when I shake it. I turned it back on to see if it would work normally but I don’t even need to turn it on, as soon as I plugged it in it began making an odd, high pitched, vibrato type sound and sucking slightly, but it certainly does not work. is this common? …. or do I have a faulty pump?