A -2 is usually linked to receiving a downvote on your question or post.

I searched your questions and answers for downvotes and only found one:

However,

This is not the reason why you lost 2 reputation points. As @sathya mentioned above, the -2 is linked to one of your deleted answers:

3 of your questions have been deleted. 1 of your answer has been deleted. Click on "show removed posts" at the bottom of the reputation tab to show this deleted post.