Due to early feeding problems etc, I have expressed every day since Floyd was born

(he now wont b/f so I express to give him EBM)
Up until yesterday I have used an avent manual pump (yep crazy I know) Yesterday I tried a medela swing pump, I have no idea why but I just didnt seem to be able to empty my breast, last night I only got 20mls off using the swing for half an hour, got my old trusty hand pump out and got another 60mls in less than ten minutes.
Is it just my (.) (.) getting used to a differnt type of pump, do I need a bigger funnel (I'm a 14 DD/E) or am I doing something wrong? Any advice would be great!!