I went on the 18th or march (last month) for my orientation to set up probation (I am on probation for shoplifting because I could pay my fine). They did an initial drug screen (which I know I failed for marijuana, as I am a habitual user. My next appointment is on the 8th of April (in 4 days) Will they drug test me again on the 8th? Even though it takes up to 45 days for habitual smokers to be clean, and what would happen if I fail?

If they have you scheduled to come back for repeat testing, yes, I would say they intend to test you again.

They are looking for decreased levels - or increased levels.

They don't have me scheduled for testing, I just have to go on the 8th of every month after that to check in and make payments. Also I over heard my P.O talking to they lady who handles the testing, the lady said is it going to be "regular, or on site?" My P.O answered "on site." What would this mean?

On site would probably mean that they are going to do a mouth swab right there in their office for drugs. Have a nice time.

Esp since you failed the first test ( they could have revolked you for that, since that shows illegal drug usage) But it is very possible that they will do a check every time you go in, that is very common, we tested almost everyone that came in but always if they ever failed one test.

So we can only assume you stopped using after going on probation, so the test levels will be much lower now.
If they are not, they may decide to do something then.

Yeah they are going to test you. They could revoke your probation its all up to your probation officer. Hope you have a cool one. You are going to have to stop smoking weed or probably do a little time.

When you get your first meeting for probation do they drug test you ?