In Jewish time keeping, do you count a day while in the midst of it. I guess an example would clarify. Let’s say we’re counting the days that have passed from Monday at 7am until Thursday at 7am. Would 3 days have passed and we would consider ourselves in the fourth day? The reason I’m asking this is because Psalm 90:4 says that a thousand years are like 1 day to God. So, if the temple was destroyed in 70AD, and we are now at 2005 AD, then using this logic we would be in the third day, right? Or would we be in the third day after 2070 AD?
Judaism counts the days from evening to evening, as in the book of Berisheis "it was evening and morning, the first day..."
Monday 7am to Thursday 7am is, as we count, Monday morning to Monday evening 1st day, Monday evening to Tuesday evening 2nd day, Tuesday evening to Wednesday evening 3rd day, Wednesday evening to Thursday morning in the 4th day.
As far as the second part of the question, we are in the end of the 6th day approaching Shabbat. (In Kabbalistic divine time keeping, and as stated in Psalms 90 that the question refers to) Every 1,000 years is a day. We are now in the Jewish year 5766, 234 years till Shabbat.
There are two opinions as to how to count. The first is we count 24 hours in a day in which every hour in heavenly time is 41.66 earthly years. The second opinion is to count only the daylight hours (12) in which we get 83.33 earthly years to the heavenly hour.