Here's a couple of things to think about.
1. You said that you paid seven days ago. How did you pay? If you paid by Paypal, for example, you may have initiated payment seven days ago but that payment may not yet have cleared. While many sellers will ship as soon as payment is initiated, some do not ship until after the payment has cleared, which can take ten days or so.
2. You point out that the seller has received positive feedback in the seven days, and suggest that this 'should' indicate that the seller has been active in that time. That's not quite a sound conclusion to draw. The feedback easily could be based on shipments that were sent before your order was placed and not received until this time. So, you can't be sure that the seller has been active.
If it were me, I'd first check the store's splash page to see its shipping terms. Does the owner wait to ship until payment has been cleared? Second, I'd consider sending a polite email to the owner to inquire about the status of the order. I wouldn't call the situation 'abnormal', but if you're concerned it doesn't hurt to open a line of communication.