yep,
kept on making that milk even after I stopped pumping. My twins were born early, so they had trouble latching, reflux and tongue ties. Weight was such an issue that I bottle fed them my ebm and then pumped after i fed them. I did this until they were 10 months old. It was a bugger getting my milk to dry up, and my boobs would still leak a little for 2 years after i stopped pumping.
I just had to make sure that i was really anal about pumping every 3 1/2 to four hours, other wise I wouldn't have enough and my boobies would get so sore and hard. I added up what I was pumping and I was getting nearly 2 ltres a day. If you can freeze your ebm - do so. Freeze it is glad snap lock bags. It is soo handy to have.

As long as you keep pumping regularly, your supply should keep up with the demand. If is starts to back off, I found some herbal tablets from the health food shop that helped. i think they were feverfew? I tried fenugreek, but they did nothing. These otherwones gave me an extra 250mls a day.
If you are still worried about drying up, try introducing 1 formula feed a day, just to get her use to it. I did this from around 4 months, as they started to get hungrier that I could make, and I just gave me some breathing space with my supply.

Hope this helps.