Maybe Im the fool

I had a horrible day at work today. My commitment to the job was questioned as was how hard I was working. I am in a tight situation because my work pays for 90% of my tuition as well as giving me a nice set check. I am salaried for 20 hours per week. I am given a lot of computer based creative projects and was told I could work from home at times. Well when I was given a large or complex project I ask if there is any reason I have to be in the office. If I am told no I go home complete the project and email it back when done. The problem is I have 3 bosses and no one to really report to. None of my bosses talk or let the other one know what I am doing/ what they have given me. They are very busy people and often out of the office so I have to contact through email. I tried to express concerns about my workload and got the brushoff. That was until today when I was questioned as to if I was doing the work I was being paid for. That hurt me. I have worked for this office for 5 years, they know me. I am a hard worker and often do projects and create things that are more than what was asked for because I know its coming. After 5 years I can read them. I am often complemented on my work and this is bull. Maybe I need to start just telling them sorry I have already but my 20 hours in for this week and Im going home even if it is only wednesday see you next monday. I cant keep going on like this. So after one of the people above me told me this and I effectively had to prove what I have done (even though projects and information are turned in every day) I was finally understood. It finally clicked to him that both of them where giving me a weeks worth of work. So now we will see if things actually get better.