I always feel off...?

I've felt like this for a long time. I almost always feel like something is different and can't really figure out what. I go from happiness, energy, and well kinda craziness to a low, depressing, empty feeling a few times every day. I feel like I'm in slow motion. Everything has a tainted feeling to it. Any ideas? It's really hard to give you guys all the details because I'm kind of flustered.