Whats the best statistical analytical method to use

I have a data set which has a treatment variable and some outcome variables which are the result of the treatments on certain markers measured daily. I would like to see if different levels of the treatment resulted in the differences in the outcome variable (there are 4 of these, each measured daily for 5 days) in other words, answer the question: did the daily outcomes vary because of the level of treatment received by each subject? I have been trying a series of analytical techniques (Manova, GEE, regression, ARIMA and ARMA on SPSS) and I am either not doing them right or I am using the wrong ones. I would appreciate any suggestions or recommendations anyone can give.