What can be causing these symptoms?

I have noticed I have not been feeling the best lately. I get headaches a lot. I get congested a lot but that may be due to allergies. I get waves of nauseousness throughout the day and have had some mild heart burn which i have experienced before. I have a couple times had a metal taste in my mouth and have waken up with leg cramps a few nights. My boyfriend was scared i was pregnant but it just wouldn't have made any sense. I took a pregnancy test anyways to make him feel better and it was negative.