Temp DB is growing continuously in SQL server
If you do a quick search on this same site, you will find lot of similar questions. Basically, some process is taking to long and is making your temdb grow until you run out of space. According to Brent Ozar "Tempdb is like a public toilette", everyone (all kind of processes) use it and usually to do filthy things. 

What you should do is locate what is making your tempdb grow, search that root cause and solve it. If you don't do that, you will still deal with continues issues like this one. You can, as a temporal solution, run a shrink on the tempdb to free some space. Please please avoid having an automated job to do shrinks.

You have several options to find the cause, running a SQL Server Profiler trace to track down Tempdb activity. Also you can use sp_whoisactive to log activity on the server while whatever causes the issue is running, so you can check that log afterward and see possible queries or processes that cause it. Kendra Little has a full blog entry on how to do this.

For some specific code samples, look here and here. Those are just some samples, as commented on first line, this a common issue, so you should find tons of useful answers here on Stackexchange site.