Do you ever just fall into a funk?

I try my hardest to remain positive in my life, even if things seem to be constantly thrown at me. Who doesn't have a life like that though right?!
The last few weeks have been especially hard and I keep alternating between feeling okay and hating everything about my life. Ugggh it's hard, but I'm also pregnant, so it could just be hormones wreaking havoc on me.
How do I climb out of the pit of despair and stay out? Any tips?