Is this the only concussion you've had? At six weeks, you really shouldn't worry, in fact if it hasn't been at least a few months you shouldn't worry, a lot of people recover in that time, others such as rydellen and myself (much fewer) longer.

Best things that helped me through the hard times were staying busy, active, and just involved in things in general. You're going to get better, its just a matter of time. I had a tendency to get really worried about when i was going to get better and I'd lay in bed all day, probably the worst thing I could have done. But if you try to occupy your time and thoughts with things (anything) other than pcs, you'll probably be better off. Stress and anxiety on top of pcs is a spiral you want to avoid. So just go about your normal day, bear in mind that it fades and comes back on in cycles like you're experiencing and dont worry so much ;-)