If you know what concept was underlying in your dream then you have already done 90% of the work of interpretation yourself. If this is the case it could get a little easier or even more confusing for you but there is a reason behind it just as there is a reason behind every dream. They all have some meaning.
If you have a dream about doubt then this means that you are worried about the outcome of something. Whenever you are experiencing a lot of doubt it means you do not trust something. If you have a dream in which someone else is in doubt of you or what you say then this means that you feel like you have lost some integrity recently. You need to gain that trust back by being a good person and letting people know you are worthy of trust.
Doubt is not necessarily an emotion, but it is a feeling in a sense, or a lack of a feeling in another sense. Rather than feeling pride or hope or seeing the possibility that could take place you are instead thinking about the fact that there are so many different ways that your life, your happiness, the current situation, etc could go horribly wrong. While you may think that it is more realistic to remain pessimistic and doubtful of your own abilities or the abilities of others, in reality it is no more realistic or unrealistic than having an excessively optimistic outlook on life. It is a fallacy that it is more realistic to be negative just as it is a fallacy that it is more realistic to be positive. The main difference between the two though is that having a generally negative outlook on things or seeing things with negative prospects leads to loss of health, loss of hope, and it is even said that pessimists and constantly doubtful people die 3-7 years sooner than those that are optimistic, no matter how misguided their beliefs may be.