For sellers in such a tight market, finding a replacement property presents challenges. A few options to consider:
Buy - Sell
If a good buying opportunity arises and you have the financial wherewithal to acquire it before selling your current home, by all means move forward. Current conditions should make for a rapid sale if your home is priced right.
Sell - Buy
Like most buyers, you may need to sell before buying. Right now, contingency offers are not viable. To be in the best position, you need to be ready to go. In this case, you can make the sale of your house conditioned upon your ability to get under contract on a replacement property within 10 days or so. In the current market, buyers are generally willing to give a seller 10 days to get a replacement property under contract. With your Realtor, get to know the frequency with which homes that meet your criteria appear for sale, and keep this time frame in mind going forward.
Sell - Rent - Buy
Sometimes the right replacement home doesn't appear in time - and moreover you may want to be in a non-pressured buying position. In this case, sell your current home, find a good rental, and enjoy your position as a buyer who is ready but under no time constraints. The right home at the right price is on the horizon.