Did you eat alot of sweets on your load days? For me when I did, that is where the headaches came from but I wasn't starving and I never had stomach pains.
Did you test the your new drops on a "dollar store" pregnancy test to confirm that they contain HCG?
Did you do your research? I researched HCG for 3 weeks before I started - YouTube, blogs and various forums, etc.
I've never heard of Intermountaion but that doesn't mean they aren't the real thing.
If the NiGen drops were fake there shouldn't be any "weaning" that you need to do. Your symptoms could truly be from you not eating enough food because none of the drops have real HCG and you ARE starving.
I hope you find out what's going on before you continue.