The fact it comes and goes rather than being there permanently is good.
To answer your questions really quickly, yes anxiety can both cause and exacerbate reflux and all digestive complaints.
And yes, 7 days is too early, you need to give it at least a month on the ppi.
Have you worked out any trigger foods? Eat little and often, don't eat at least 3 hours before bed, if it's bad at night, get a wedge pillow or prop yourself up at night.