My problem is that I live in California. If I lived in Iowa or New Hampshire or something, it might make a difference. California's primary is not until June, however. By that point in time, it's very possible that the primary election will have already been decided. Bernie may have dropped out of the race by June, or ideally he may be in such a strong winning position that my vote wouldn't matter.The only thing that can hurt him is voter apathy and name recognition, so if you're a US voter then instead of "liking to believe in him" just believe in him and be sure to cast your vote for the democratic nomination. I hope I'm not making too many assumptions about your party affiliation. I also don't want to become too overbearing in my Sanders zealotry, but try watching this video aimed at those who like Bernie, but don't know if they should support him as opposed to Hillary. It makes his campaign make a bit more sense and presents a clear case that his election is not a pipe dream.
For my vote to matter, the primary election would have to be very very close by the time June rolls around. That isn't likely going to happen because there are dozens of states that get to vote first and have a bigger impact on the outcome. This system really screws Californians. Puerto Rico gets to vote before we do. Ideally, I wish that all states and territories could just vote at the same time.