Why did my consecutive days disappear?
I was visiting the site every day for many days, and suddenly today the consecutive counter was reset, - so my question is - my it own fault or a bug from server side ?
Probably your own fault for not visiting every UTC day.
For example, if you're in a time zone with is UTC-8 (e.g. California) then you could visit at 3pm on Monday and then 5pm on Tuesday (both local time) - but the system sees that as 11pm Monday UTC and 1am Wednesday UTC, with no visit on Tuesday.