What Causes Dizziness And Nausea After Finishing A Period?

I have a concern about some things that are going on right now. I just finished my cycle yesterday and had my tubes tied several years ago but I am worried about some things that have been happening to me in the last few weeks.
In the last 2 weeks I have been experiencing a growing number of strange symptoms. Starting 2 weeks ago I started getting light headed and dizzy...sometimes nearly passing out. In addition I would have spells where I thought i would vomit. Then today I was fine on the way to work, didnt eat or drink anything before I left as usual. I got to work got my coffee as always and took a few sips then threw up. I felt sick most of the day and when I got home with dinner I ate far more than usual and am still hungry but no longer sick at all.
Any ideas what I should be concerned about?