Hey Yeru, I tried that 'send a message' to you, I hope it worked.
I have received only one message from another poster, and it seemed to work, so I hope it did for you.
Just in case it did not, the elixir: echinacea (tincture) should be available in the USA (I think) @ Walgreens or CVS or similar drugstores. Wherever they sell vitamins/herbal tablets, it should be there.
Ask the pharmacist at the drugstore, they are usually very aware of echinacea.
I'm in Canada, so I can pick it up at the local drugstores here. When I was in Cleveland, Ohio last year, I saw something similar to what we had here, there. (Cost $8 to $10CDN - $5 to $7 US dollars).
It worked like a charm, and I swear by it. Only side effect, it does go through your body rather quickly and you may have to use the washroom facilities for a little while, but that's the only negative thing...if you'd even want to call it that.
Get well soon Yeru.