It's normal if your particular subdivision on does six sales a year. In a case like that you're only looking at one bona fide buyer every 60 days, and maybe you've already had five sales this year.
It's also normal if you're in an elevated price range. In my home market it's not unusual to have over 100 homes priced over $1 million. Yet, only 14 may sell in a given year. That means there are only 14 bona fide buyers out there, period. Furthermore, fully 86% of those homes will fail to sell simply because there are not physically enough buyers for homes in those price ranges.
Real estate showings are cyclic...you can go weeks with very light activity and then four showings in a day, it happens. But if you are in a neighborhood that has numerous, regular sales it still is not such an issue in the first two weeks, but if it gets to four weeks then it's time to look at the price, the terms and the housekeeping.