What time system does the Streak use? Why did my streak break?
Your streak will not break without reason.
The streak window extends till 2am and as long as you meditate before that, your streak will remain active.
An example of this working:
1/1/20 - 10am (streak 1)
2/1/20 - 7pm (streak 2)
4/1/20 - 1:23am (streak 3)
4/1/20 - 10am (streak 4)
Be careful when meditating on multiple computers as Steam cloud might not synchronise correctly and you could lose your streak. Playne does store a backup save in your save folder, but it's worth being mindful of this feature.
If you still think the streak should not have broken, then drop me your save file to email@example.com I would be happy to take a look for you and let you know what happened.