Hi,
I have been expressing milk for our daughter daily, except on weekends when she grazes freely. (she is six and a half months old and on three solid meals a day)
I haven't had any problems whatsoever with producing milk. I pumped 300mil twice a day, and then she would nurse about two full sessions when we are at home once before bedtime and about five in the morning;
All of a sudden my milk is almost absent;
On the weekend I caught the flu and have been drinking an immune booster with echinacea, garlic, and elderberry extract. (could any of these ingredients be the cause?)
I have noticed that our girl is drinking more frequently at night, but the last thing I suspected was a dwindling milk supply...
Since Monday I have been pumping twice at work and twice at home and only manage 260mil for the effort,(that amounts to 80minutes a day) I am drinking lots of water and getting rest, I thought that my milk would gradually become more and more again, but the situation is actually worse.

My weight is five kilos under my normal before pregnant weight despite me eating more than usual (about 5 small meals a day) and trying to gain, doesn't seem to happen mil eating more, my hair is falling out, I am not tired... could nutrition be the culprit?

I really do enjoy breastfeeding and would try anything to get back what I had, I'd especially love to see our girl through the winter with mommybiotics, please what can I do?

It's not likely the immune booster is the culprit. All of those things are considered fine, at least for short term use, while breastfeeding.

Could be a number of different possibilities. Most likely just natural reduction which often happens around midyear or so. This is because many babies no longer require as much as before so your body no longer needs to keep the same level of production going. Prolactin levels tend to naturally decrease around this time as well. Add to this that if she is having more feeds from EBM instead of actually being at the breast for the majority, this too can effect supply. This is because she will do a better job of moving the milk than the pump will, even if things have gone fine before, levels from pumping will often fluctuate. Her more frequent night feeds may also be due to a growth spurt so she is naturally trying to boost your supply.

You can try adding something like fenugreek to your diet, along with more frequent feedings of her being at the breast. Increasing the frequency of at the breast feedings over a week or so may be enough to make some difference.

Your weight loss and such may be from having had the flu... might also have temporarily effected your milk supply. Continue with taking care of yourself... eat well and a decent amount of fluids... (you don't need to go over the top with it though). By chance have you taken any decongestant? That can sometimes effect milk supply as well.