Can bipolar disorder cause self-doubt and low self-esteem?

Yes, and those are two of the many reasons why anyone with bipolar should be working with a therapist. Depression, self-doubt and low self-esteem always work together. The euphoria of hypo/mania is the opposite but when it ends you are left with the poor decisions and possibly behaviors to clean up. When balanced you know you can swing without any real reason and can feel like you don't really have much control over yourself. Unmedicated, this snowballs into a bad place. When actively managing the illness it gets better. You can take back control which improves self-confidence and sense of self-determination. Finding a good psychiatrist and hanging in there until meds that work w/o untenuable side effects is a big move. Working with a therapist to deal with the baggage of the past, accept that it's a disease and not a character flaw, and perhaps most importantly how to manage your life in ways to reduce episodes and manage yourself thru them to minimize consequences. So, yeh, it can do the things you mention, but you can also take action to overcome them. At least this has been my experience.

Have you been diagnosed as bipolar or are you attempting to diagnose yourself?

In the depressive points of a cycle, a person can feel self-doubt and low self-esteem.

Linking to symptoms on wikipedia in sources.

yes....but you need to be sure that its bi polar and not depression cuz they are 2 totally different diseases.which both can make you feel that way

yes it can, but so does other mental disorders.