Can someone help explain

Has anyone had this happen to them or can explain this.....Today I went into work and cleaned my studio before my class started and I had to stop because I started feeling light headed and my hands started shaking. I had my husband bring me a water and snack which seemed to help but an hour later we went to dinner with his parents and I was hungry but nothing sounded appetizing (I ended up getting soup). I've been getting more headaches and heartburn the last couple days and I've been so tired even though I've been getting between 8-9 hours of sleep a night. Just wondering what this could be?