I Take St Johns Wort Which Is 3grams Included With

I take St Johns Wort which is 3grams included with b vitamins. All in one vitamin tablet.
I started with a throat infection on 31st Aug and that has gone but now have a bad cough and have had a lot of phlem which Is mainly clear but is also a little green after getting up from sleep and feeling week and heavy in chest. I have amoxcycillin 500mg which are still current that was prescribed after dental work but I never took them. Would this medication if I took it interact with the Dt Johns wort. It maybe a few days before I can get into the doctors as I live in a remote country town.