Check to make sure you have not inadvertently changed your location to calculate shipping to a country those sellers do not ship to. Doing so will hide items that do not ship to that country.
Try a general search using a common keyword that produces many results, then change the sort to "Distance: nearest first". You should see an indication of your country or postal code at the top of the search. Change that if it is incorrect. Then try searching again using your preferred sort order.
