Well, it could be totally normal. Many people have "episodes" or periodic times of depression that recurs. How is your sleep? Getting enough? That could cause mood swings but so could other things. If you felt suicidal, then flipped, as you say, to feeling totally normal, what does normal feel like to you? I've read enough here on the forums to wonder if you could have bipolar, but we aren't able to help you figure out if you are. You should be seeing a doctor for advice, being suicidal, even just thinking of it at times in your life, deserves some professional intervention. Best wishes, and a warm welcome to this site!