There are two things that are different: 1 ) "to suppose" which means to think or assume something. 2 ) "to be suppoesed to" which means you should, or you have to do something. Examples for case 1: "What do you suppose this means?" (= "What do you think this means?") "What do you suppose I should do in this situation?" (= "what do you think is the right thing for me to do in this situation?" "He supposed that I would go, but he was wrong" (= "He thought that I would go, but he was wrong" Examples for case 2: "What am I supposed to do?" (="what should I do?) "What is a person supposed to do in a situation like this?" (="What is the right thing for a person to do in a situation like this?") "I was supposed to eat only an apple, but I ate also a peach!" (="The decision -eg by a doctor, or by my mother, or because of a diet- was that I should eat only an apple, but instead I ate also a peach!" So your sentence is a bit strange. I don't know Spanish, but in English you could say: "What was I supposed to do!?" (="I really could not think of a better solution, this is the only thing I felt was right to do") "What is a person supposed to do in a situation like this?" Or using both 1) and 2) you can say: "What do you suppose that I was supposed to do?" (="What do you think that was the right thing for me to do?" (Due to the repetition of suppose and supposed people will choose a different expression usually, like for example "What do you suggest/think that I was supposed to do?") I hope this helps

Some examples: 1. What am I supposed to do? 2. The book is supposed to be based on a true story. 3. I was supposed to go to Italy in November, but now I can't go.('supposed' must always be followed by 'to')

I am suppose to be at the park by 3:00pm. I have to be at work at 8:00am. (tengo que?) I must be at the airport by 6:00pm in order to catch my flight. (deber?) These three phrases are similar. I am learning Spanish, and do not know enough yet to tell you what would be the equivalent in Spanish. "Suppose to" does not convey an absolute necessity. "I am suppose to be at the park by 3:00pm, but if I am a little late, it will be okay. I must be to the airport by 6:00pm, or the plane will leave without me--I cannot be late." In order of expressing a greater necessity, from least to greatest, I would put the three phrases in the order above: suppose to, have to, must.