Depression or just emotions?

I ask this question because I have this problem of crying a lot. Im 14 and I figure it just my emotions. But then again I think its some type of depression. Its like a off and on thing. I will be happy for a moment, but then, I start to cry for some...

reason. I think Im bipolar but Im not sure. I have this thing of like feeling sad one minute then angry then happy. I cry at all sad and emotional movies and songs. I sometimes think of suicide but its not severe. Can it be some type of depression or could it be that Im going through puberty?

I had that before when I was about 12 I think I don't think you have bipolar. Just try do things that make you happy at first it going to be hard but later it would get better. I went to see my dad for example and I haven't seen him for more then 2 years and I was so happy to see him.

Yeah, it could be some sort of depression, and maybe a little bit bipolar..
But, I'm not a doctor. Lol,

But I have those same problems.
I could be so happy, and the littlest thing will put me in the worst mood.
Sometimes I get angry for no reason, or for something stupid.
Also, I get depressed sometimes.. It lasts for a few days.
I get to the point where I don't want to do anything but sit in my room and listen to music. I turn my cell phone off, I don't eat, or I eat a lot. I won't talk much.
It sucks.

My mom is bipolar and she says that I most likely am too.
Hah, so I guess I am

See, that the same problems I have. Like now I can tell when im feeling depressed cause sometimes I wont eat or other times I will eat too much. I got to the point where when one of my friends talked to me, I wouldnt listen and she thought I was ignoring her. I had to tell her I wasnt feeling good or I feel sick. Then like I would be happy a couple days later, talking a storm. Its insane. I want to talk to my parents or someone bout it, but I dont know how to. If it is bipolar or some type of depression, I know I have to get some help. It got worst after like two or three months after I started 8th grade and then, it cooled down. Now, it'll just go off and then on. Like one minute I would be listening to something and start crying for no reason. When I think of something sad, I cry. When someone touches me, I get angry but then, be happy with the person a couple minutes later.

I just need to know what is wrong with me.