I would go and get checked out. Especially with the suicidal thoughts. Better to keep yourself safe.
Yes you should seek help,Please don't wait. If you ask for others approval please know you don't any ones approval. You deserve to be well. Good luck
It definitely sounds like you're in a depressed state. Just go to the hospital like ILADVOCATE said. They will have a psychologist or psychiatrist speak with you and determine if you should be admitted or not.
If you are having suicidal ideations of any kind it would be crucial to go to the walk in clinic at a hospital and they can make a decision as to whether you need to be hospitalized after speaking to your psychiatrist. Some of the other concerns you are expressing such as feelings of guilt and loss of self worth as well as changes in sleeping and eating patterns can occur in depression and the depressive aspect of bipolar though only a psychiatrist would be able to understand the specifics. There are new mood stabilizers approved all the time so there are an increasing number of options:
http://www.psycheducation.org/depression/meds/moodstabilizers.htm
If you have tried all commonly used options your psychiatrist could refer you to a mood disorders specialist. However right now the crucial goal is just to be stable and safe so going to the hospital might very well be the right option. Cutting is a specific concern that responds not just to medication alone but talk therapy and especially cognitive behavioral therapy and you discuss this with your psychiatrist as well. There are also specific support groups for this.