Fortunately or unfortunately it is already hard to remember when my lo was 7 weeks old. I do know that I wasn't doing BW (didn't find it til he was 4 months), and when I DID find BW, our 45 minute nap issue was due to an overtired/overstimulated baby.
I never realized how easily a baby could get worn out. i was under the impression (baby books, TV etc) that I had to be "Involved" at ALL times to be a good mom- singing, talking, showing pictures.
Anyway. When I realized that too much was going on for him and (even at 4 months) toned it WWWAAAAYYYY down, the 45 minute naps went away in 3 or 4 days.
Worth a shot. Please keep us posted.