Yup. You began the transaction twice and committed it once, thereby leaving the transaction open and all locks still held.
If you'd checked @@TranCount it would have shown 1, and DBCC OpenTran would have shown your change (assuming that it was the oldest open transaction).
p.s. Ad-hoc, unchecked changes to a production database? That's just asking for this kind of problem and worse.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability