Pumping? Please help!!

Does anyone have any advice on pumping? After my let down I don’t have milk flow...like it just stops and will only start again if I pull off the shields and reattach them to myself. But then the flow will only last a few seconds before stopping again. I go back to school in summer and really need to be able to pump if I want to continue breastfeeding.

I know it’s not a supply issue as my baby went from 7.10lbs to 9.4lbs in 7 days. I also got different size shields to make sure I had a good fit. I went to the lactation clinic at my hospital and all they tried to do was sell me a hospital pump that I can’t afford 😞