Start with a simple and open source task tracker. It will be very handy in long run. It would also be an opportunity to learn a new type of tool to help you.
There are many alternatives to choose from. The one that i am using is Task Coach. It is a Free flexible open source todo manager featuring hierarchical tasks. You may also get a number of YouTube videos on how to use Task Coach here.
However, my college prefers Trac. This tool offers an issue tracking system and more. It runs by default with SQLite which means plain files. No need for a database server.
(although Trac can be configured to use MySQL or PostgreSQL, too)
However, depending on your changing priorities you may switch to a different open-source task tracker. There are couple of them which are very popular:
The following article which specifies features - 11 Open source project management tools.
However, if you look for comparison then the following Wiki page has most of the information.