You are correct about what probably happened. Same thing happened to me when I subscribed to a different club. Its ok though, just stop it and let it recharge... Its actually good because it will force you to comment more and interact instead of just upvoting...
And as far as feeling guilty, don't. Everyone goes through this process and realizes that people only have 10 votes a day. there are many more than 10 things everyone would like to upvote. So the way to recognize something really good is to resteem or comment. I think both are equally valuable and I am very flattered when I see someone do that for me.
So no worries, just expand the ways you can show your respect and this experience will be a very important positive for you in the future!