Is it true that a metallic taste in your mouth is a sing of pregnancy? Did anyone experience this at the early stage?

Yes I experienced that all the time it's called Dysgeusia. Pregnancy hormones cause our taste to fluctuate widely and gets better after the second trimester (but not for me). It is recommended to combat the taste in your tongue with sour flavours but I feel that the effects don't last. I tried salty too depending on my mood. Another way you could try brushing your tongue or rinse your mouth with some saline or baking soda solution. If none works for you, then you have to either wait it out or tolerate it. http://www.whattoexpect.com/pregnancy/symptoms-and-solutions/metallic-taste.aspx