Hey Burçu, that's been a powerful introduction - welcome to Steem!
There are a few things you should know about this network. One of the most important things to consider is that your interactions are limited to something called RC (ressource credit). You can monitor your numbers on this site for instance: https://steemd.com/@burcucelik

Currently you don't have enough mana (ressources) in order to do more comments, for instance. So you should wait a couple of hours until your power is recharged: