I'm using the TT electric breast pump but every so often it seems to stop working like there is a gap in the vaccuum somewhere. Usually I check all the parts and it will work again. Have taken it apart and put back together about 10 times this morning and can't get it to work - it was working then suddenly stopped pulling. anyone else has this problem? Wondering if it's faulty or something I'm doing. This expressing is time consuming and daffy enough without this hassle!