Bachelor thesis with same topic I've successfully defended my bachelor thesis.

After some months I've been curious to see if there are any other thesis with the same topic that I've chosen. I found some that are similar to mine (from previous years at universities from other countries). The topic was about, to test a set of algorithms againts specific input.

Is it bad that my thesis is really similar to these other theses ? Basically the only difference is that, in my thesis I tested the algorithms with different inputs / input sizes, also most of the algorithms that I've chosen matches the algorithms in the other theses, with the exception of 2.
For a doctoral thesis this would be bad, but not so much for a bachelor's thesis. Assuming that you worked independently of the other work (i.e. no plagiarism) then your work has value to you for personal development. 

You don't have anything publishable, of course, but you did learn something about research process. But, for later work, you will be expected to spend considerable effort in a literature search to know what has already been done with your topic. This is harder at your level due to lack of time (fixed deadlines) and the fact that not such work is available (i.e. unpublished). 

If your faculty and university are happy with your work then you should be also.  But as you move on, the standards get higher. 

One major difference is that a bachelor's thesis is expected to be done in a fixed amount of time. A doctoral thesis has no such constraint and some take a long time to complete. So the very nature of the problems that can be undertaken at your level is very constrained. 

But let your advisor and/or faculty guide you here. The fact that you had a successful defense is a positive point in your favor. Relax and congratulations.