How to annotate 13 nts sequence

[Palgrave]

I did smallRNA sequencing and detected 3 types of sequences that where 13, 14 and 15 nts long. In total they had about 30 mill reads.
When I run blast I get too many hits to make any sense. How do I go along to annotate these 3 sequences?

Regards

[rflrob]

You might try checking out miRBase: http://www.mirbase.org/