Can I still take out loans after consolidating? Best way to consolidate federal/private loans?

I have a lot of federal loans from college, and even more private loans (sallie mae) from the past few years where i attempted to become a doctor (medical school loans, but i could not finish). i'd like to consolidate now, but am going to pursue a masters degree in clinical research. should i hold off on consolidating until after i get my masters? and any and all info that might help me or direct me towards loan consolidation would be greatly appreciated. i'm really new to this. serious answers only please, as i already know i made many mistakes in my life. thank you.