Ok I can see why you have issues.
Look at your front for example. The sole focus is your AF, and chanelling through balls to him. It is very one dimensional, so when it works it, you score. When they mark him out, you have no way to score goals.
This is made much worse because you are playing as a high rep side, which means team typically play quite deep against you, especially at home. Its very hard to get through balls in behind a very deep defence. So your AF is struggling their attentions, getting the ball under a lot of pressure, and firing away poor/tough chances.
Defensively you are getting creamed because you are playing high up the pitch, they soak up your poor/difficult chances, and then hit you hard on the counter. You are also playing a large number of specialists (the 5 playmakers) in a philosophy (fluid) that is ultimately designed for generalist roles (such as centre mid/attacking mid etc)
A few questions that you need to try and answer yourself so you know what you are trying to do:
1) What kind of forward do you want Falcao to be? A pure spearhead? a link for the midfield? a bit of both. Do you want him to his real life role, or another real life role.
2) Why did you pick fluid?
3) How and where do you want you team to attack and create chances?
4) Do you want to be playing with 5 playmakers? Or did you pick them because you felt they fit the players?