It sounds more like a clutch problem. I suspect some air in the hydraulic system and suggest bleeding to clear out the air.
Usually a fluid related problem shows up more in cold weather, and since the weather is warming up I think this is less likely. If you have the factory fill in it, or if you have straight Mercon you would benefit from an upgrade in fluid, something with a bit more friction modifier in it. The least expensive fluid with a higher level of friction modifier in it is ATF+3 (which works very well). The premium answer is Ford Honey (preferably with a little Ford friction modifier added), Torco, Royal Purple, or Specialty Formulations.
