Firts off stop with the pesticide your spraying the poor lil thing with,then get it out of that pot with the green alge growing on top & plant it straight into the ground,then throw away all fertilizers you've been giving it,its very hard for a plant that small to have a nitrogen deficency,whats happening is your killing it with love by constantly overwatering it & feeding it fertilizer when it dont need anything other than to be left alone.
The reason you were told to transplant out of that pot is because from the constant over watering you've turned the soil into sludge that will never fully dry out,plus with the over feeding you've fertilized the soil to the point its contaminated,the fungus growing on top of the water layer is evidence of toxic salt build up.
Obviously you've had pest problems,after transplanting remove all vegatation in a 3 ft circle around the plant base,this makes it harder for insects to gather round your plant for the feast,at the very least it makes your plant less desireable.
Weather your growing in a bad location or not that plant needs to come out of that pot & it needs it right now,im not shitting you on the fertilizer either,stop feeding that thing & forget about fertilization all together,if you think im giving you bad advice thats cool too but stop & think for a second,the route you've taken with that plant so far has got you one hella sick plant,maybe it's time to realize that you really dont have a good grasp on growing & that you need to take an entirely different approach, instead of looking for a miracle cure that fits the ideas you have about growing.
If you do not transplant,lay off the water & stop feeding it fertilizers your plant will never get any better & that you can count on.