It 'might' be related to the ultrapeers you are connected to. Patience is best as Ultrapeers come & go usually. However you could try closing & opening LW to see if any improvement. Some days are simply better than others. Also, if you use one identical search too many times it may in fact have a negative effect with your ultrapeers who may consider it some kind of spam. Again, different UP's or patience is best.

Did you try an All Types search also to see if anything shows up? All Types search tends to attract spam however was just curious to see if anything showed up.