I wouldn't be using Zillow OR Trulia to determine your home's current market value. These sites are notorious for having inaccurate figures. Plus, it takes months for sold properties to appear here. THey are using comps that sold 6-12 months ago. A lot can happen in a few months. Plus...They use algorithms that don't take into account things like location, updates, lot size, etc.
If you are thinking about selling, you should find a couple of local REALTORS who can give you a detailed comparative market analysis (CMA). This will give you an idea of what homes in your area have been selling for in recent months, that are similar in size, style, location, etc.