I want to echo everyone else to say that your DH isn't being supportive, helpful or encouraging. I have a chronic low-supply issue due to insufficient glandular tissue. My husband was so awesome w/ both kids, it would have been very difficult to be successful with him.
That said, I think you need to talk to your DH when it's not a feeding time. Explaining why BF is best and why it's important to you. Explain that you are working with medical professionals to figure this out and that if they thought your current plant was not working, they would tell you. I hope he comes around. It is hard, exhausting challenging, frustrating, etc. But, you really do need each other.
I would keep meeting with the LC until your supply is back. I would not give in to a bottle, finger feeding or supplemental nursing is much better at this point. And I know it's hard b/c I used a supplemental nurser for almost 24 months total between my 2 girls. Did she evaluate his latch and mouth for any problems there? Make sure you are eating enough, drinking at minimum 64oz a day, but probably much more. Nursing burns 500 calories, so you must be eating that much extra. Try eating oatmeal, try out some herbal tinctures (More Milk Plus by Motherlove is better than plain fenugreek in my opinion) and get sleep as much as possible.