As of this evening my right boob is really engorged so I thought I'd express, but only a little bit came out and I sat for like another 20 mins and not a drop came out. I had to give up in the end as the vacuum was starting to hurt!!! I've put a hot flannel on it, but nothing happening. I'm worriedim going to go to bed now and wake up with mastitis! Why's it not coming out??? (I've massaged it etc...)