Exhaustion

I have never in my life been as tired as I am these days.  Not even when I had mono last summer did I feel like this.  Yesterday I managed to get up, get a shower, and get clothes on but by lunch time I was wiped out.  My wonderful husband told me to go take a nap...I slept for nearly six hours.  He woke me up so that we could go to a graduation party.  After two hours at the party I was so tired that I felt like weeping.  We came home and I went straight to bed.  Joe decided that we were skipping church this morning so that I could get extra rest while he was at home to watch the boys.  I am typing this from my bed this morning.
I am tired of sleeping, but still don't feel rested.  I really don't think this is normal.  I am past the first trimester of this pregnancy, so I don't think this is pregnancy related.  I see my OBGYN on Tuesday, so maybe he will be able to provide some insight.  Anyone else ever experienced this?