Sudden Exhaustion?

Hi all,

This will sound odd and pretty vague, but I’ll give it a shot. I’m almost 19 weeks along, and this afternoon very suddenly, I became very exhausted, to the point where it feels like I have a big illness coming on, if anyone can understand that specific feeling. I don’t know anyone that is sick, and have literally been isolating myself to avoid the flu, and religiously wash my hands - so, I guess my question is, can this be hormonal? Does anyone else feel like this with such a rapid onset?