Get ready for the press to lie about you. Trust no one. You are probably being arrested because you allowed somebody else to know what you were doing. If you do get caught, you had better have studied up. It might reduce your sentence by half or more.
After you have been convicted of some crime(s), they will calculate the duration of your sentence. Here is the freaky thing. The length of your stay will not only depend on the crimes you have been convicted of. It might might also include other crimes that were not even brought forth against you.
Get a lawyer. The best bang for your buck will be one that specializes in sentencing. It would be best if you knew the United States Sentencing Guidelines (USSG). Don't put your hopes in beating the Fed. They have a 95% conviction rate. Try to minimize the damage and your time in the slammer.