If your streak reset, it means you missed a day and had no freezes left.
Freezes recap. Two quests in a day earns one, maximum two held, spent automatically on a missed day. Missing two days in a row with one freeze uses the freeze on the first and resets on the second.
Things that don't break a streak: not spending your coins, not opening the app, or opening a blocked app after paying for it. Only a day with no completed quest counts as a miss.
Something that surprises people: starting a focus session doesn't count. Finishing it does. A session you abandoned halfway doesn't record a quest for that day.
We don't restore streaks by hand. It would make the number meaningless, and the number is the only reason it works. Day one again is genuinely fine; almost everyone here has done it more than once.