Hi,

BIG hugs for you I just had mastitis, I hope you don't get it again, it sucks BIG TIME! I think you're doing such a wonderful thing for your DD, expressing for her

Can't really help with the 'thread' you are expressing, but I hope it clears up for you soon.

WRT expressing, make sure that when you position the pump you change WHERE it is multiple times during an expressing session. I have been expressing since 2 weeks and I know that if I don't reposition and make sure I drain the breast evenly I will get a lump (I think I got complacent which caused the mastitis). A manual pump is fine I would say (I have both and can't imagine trying my electric while having mastitis OUCH!).
Try and express at the same time/time intervals each day, that should also help with supply *I think*.

Have you tried massaging with a warm/hot compress, or bathing your breast in warm water, before expressing to help with let down? That may help...?