Hi zzarur,
Test Day is a rather specific 'event' - the details are specific and they matter, so you have to train as best as you can for all of them. The more realistic you can make your CATs, the more likely the score results are to be accurate. The more you deviate, the more "inflated" your practice scores can become - and that's likely what happened here. By skipping the Essay section, you took a shorter Exam that requires less effort and energy than the Official GMAT will require, so this score result is likely not accurate. In addition, if you did anything else that isn't realistic, such as taking the CATs at home, taking them at different times of day, pausing the Exam, etc., then the score is likely even more inflated. As such, you have to be more specific about how you take your CATs in the future.
That having been said, raising a 590 to a 700+ will likely take at least another 2-3 months of consistent, guided study. This is meant to say that a June Test Date might not be a practical choice with your current score goal. Since it's been almost 3 weeks since your last CAT, I suggest that you take a new FULL-LENGTH CAT sometime soon (perhaps this weekend). Once you have that score, you should report back here and we can discuss how best to proceed.
GMAT assassins aren't born, they're made,
Rich