Restarted breastfeeding, HELP!

Hello mommies... I stopped breast feeding when my LO was about 5 weeks old. Now he is 10 weeks going on 11 weeks in 2 days. When I squeeze my breast a little milk (or may be colustrum) comes out but that's it. I tried pumping and a drop of milk stays on the nipple and I do not have enough to be pumped in a bottle. My Dr said I should be able to restart again, can you make some suggestions to get this going again? I'm drinking lots of water. Should I try taking a supplement? Has anyone experienced this before trying to pump again after weeks without pumping?