What Causes Light Periods,cramping,nausea,bloating And Insomnia?

My mentrual cycle has been a bit off for a few months, meaning 5 or so days of spotting before my period starts (this has never happened before) and now for the past few weeks I have been experiencing nausea and low blood sugar in the morning about 10 mins after I wake up, sever insomnia with crazy dreams all night long, bloating, mild cramping, I had to have meat the other day after not eating meat for 11 years. I took a pregnancy test yesterday and it was negative. Could I be pregnant anyway?