14 weeks and concerned

Today I'm in all aspects officially in my second trimester. They say you should give it a couple weeks to feel "back to normal", but my symptoms are only getting worse. Call it mood swings or whatever, but I have just felt down and sluggish. Totally not like me at all. It's almost like I'm depressed about being pregnant which is just not the case! I'm excited. Most of the time... Help, please? I don't know if I should be worried or not.