SAT Scores Much Lower Than Expected

I just got my October 3rd SAT scores back and to be honest I do not understand how I scored so low. My scores were

CR 600
Math 620
Writing 650 with a 10 on the essay.

Over the summer I took the Green SAT system online course. My first full diagnostic test out of the blue book I got a 1980 with a 690 in math, 700 in writing, and 590 in reading. After a few more weeks of the program I got my score up to a 2070.
I finished the program in mid August.

For a month up until up to 2 weeks before the exam, I was not studying as frequently as I was supposed, taking only 3 or 4 practice sections a week and no full tests because I was so busy. Two weeks before, I began to study like crazy. I realized that I was quite rusty, but by one week before the test, I was doing about the same in critical reading and writing in sections, and somewhat better in math sections. During the two weeks before the exam I was taking 3-4 sections a day, and I was scoring consistently after the first week in the 700 range for math and writing and around 650 in CR. I followed the program of getting good sleep the week and night before the test. I do not understand why I did so poorly and it is getting to me.

I was not stressed at all during the test and the sections felt as hard as they normally are.
Also, maybe I’m just being ridiculous but is there a chance my scores are wrong?

Please help me. I need help to figure out what went wrong.

Thanks a lot

More evidence that the vaunted Green System is more flash than substance.

I got results in full tests from the blue book so its not flash