Can i still brestfeed after 3wks of not pumping?

My son is almost a month old and I began pumping in the hospital, but not religiously. We came home and it was much harder to pump. My son was in the nicu for about 2wks where they bottle fed. I tried offering my breast and wanted nothing to do with it. My question is can I still try to pump again? I squeeze my breast and I see little milk come out. I would like to know how and what mothers do to produce and keep their milk? Is there still a chance for me? And how long will it take to produce alot of milk?? Thanks!