I also pumped too soon because I went back to work part time very early on, but then I ended up just nursing the baby at work and was . I do think pumping too early drove my oversupply too.
with everything joe.s.mom said. Backing off the pump and block feeding will help. Work out any clogs and be on the lookout for signs of infection. I used to massage my breasts in the shower to work out clogs. A warm shower seemed to be the most effective means of loosening the clogs for me. Milk would spray all over the place. I took a lot of showers back then for that reason alone.
It might help to keep working on laid back nursing. It took us awhile to get it down. Recline a little more or a little less. Switch around the position of the baby on your stomach or chest. In the beginning, I was even sort of holding my baby over the nipple and lowering him down as he latched.
Be patient. All of these things can take some time to work. Oversupply can wax and wane as you head toward improvement. But it does get better, and sticking with it is so worth it in the end. You can do this!