Anti anxiety is something with Blueberry imo. Blueberry known for being very euphoric. Do you have any idea what strains you have been smoking, like are they pure sativas? Sativas are known for being anxiety producing. The problem with just going "indica" to avoid paranoia is you also end up often with a strain that makes you less likely to do things and enjoy yourselves, ie couch locked. A good skunk strain will already be around 25% indica and I find less paranoia with my skunk as long as I don't smoke a lot. As much problem as I had getting my order from Peak, most people do not. Unfortunately I have Northernberry coming from them, not that it's a bad thing, just that it's heavy indica and I already have quite a few. But they just got their Skunkberry back in stock and that means the seeds are probably very fresh. If I were ordering from them today I'd get Skunkberry knowing the Blueberry side would take a lot of the sativa edge off but more importantly in itself produce a very euphoric high that's typically not couchlock on its own.
If money were no object I think Strawberry Cough is pretty good for anti anxiety though. The reviews I've read for Resevoir Strawberry Diesel show two phenos and quite a few people comment that the SC leaning one isn't very strong though so I tend to wonder about it, but it was also supposedly made with a SC cut that's not Dutch Passion's so who knows.
There's also a strain on Seedbay right now by a breeder called annaC that's Yumbolt x Alpha Diesel(yummyD) and only $20. Each of those strains would cost you $80-$100 not to mention it is already crossed for you. AnnaC's stuff is supposed to be top shelf. Yumbolt is a very laid back indica with a narcotic feel so might be good for headaches and no paranoia.
One potential set back with buying a strain just for pain is that once your gf smokes she's probably going to be really laid back and not into doing much. Real "pain" strains are generally heavy.
Here's a thread with some medical strain types but some of them are not available anymore. If your gf is looking for a strain specifically and only to relieve migraine I think Sour Bubble is probably the most potent I've heard of. PM me if you decide you want to find it because there are some seedbanks that carry it or will be restocking.
http://www.greenpassion.org/f11/medicinal-strain-database-6781/