Just a thought buy maybe you've concentrated on learning lots of chord shapes and not on actually playing any songs.Depend on musical tastes but most people simply learn 2 or 3 chords, pick out a song they like and play it over and over again ( formed a basis for careers in the case of the Ramones and Quo). With a few chords you can concentrate more on the rhythm/strumming pattern than watching you finger positions.When you feel proficient with that song find another with a few different chord shapes and so on.
If you can actually produce something recognisable fairly quickly(however simple) it will give you the incentive to keep practising because you really do have to just keep at it and it comes easier if you are enjoying it.
Also always good to have a friend to play with as you will pick up things from each other.
With regards the plectrum thing they are slippery and can be dropped easily particularly if your hands are sweating a bit.(even the professional have spares stuck to microphone stands)Try scoring the bit of the plectrum that fits between the finger and thumb or a different thickness.
This problem will decrease as you become more proficient.
Keep at it and good luck