It doesn't necessarily sound bipolar, but I am not a doctor. If these episodes are interfering with your daily life, you should make an appointment with a psychiatrist. I see you went once, but one time is not enough to make any sort of impact. Medication may help, but since you are saying a lot of the problem is your thoughts, you might want to look into cognitive behavioral therapy. Again one time will not be enough to be helpful, but if you go regularly you can learn how to reframe your thoughts. You can also look up cbt online.