Getting my supply back

So basically I'm dried up. I wasn't pumping like I should have been when my supply dropped and I had to supplement with formula. I contacted a lactation consultant and she told me to pump every 3 hours even at night and my supply should come back (not doing great at that because it's so defeating when basically a drop comes out). I tried breastfeeding today just to see if he would latch and he was soo not interested. So my question is, can I get my supply back up with just pumping? I'm also taking fenugreek, brewer's yeast, flax seed and oats. I'm 13 weeks post partum as well, i switched to all formula probably at 4 weeks.