One of the hardest things for most people is to feel like they aren’t in control of themselves. It’s confusing and sometimes even scary to feel like you don’t know where your feelings will go next. Since you are a 14 year old girl, it’s possible that the ups and down you are experiencing are the result of the cascade of hormones that occur during puberty. It’s also possible that you are growing so much that your body hasn’t adjusted to itself. I think it would be helpful for you to see your medical doctor for a complete check up first — just to make sure that there isn’t something like a vitamin deficiency or a thyroid problem going on. Then educate yourself about what happens to girls physically and emotionally during puberty. You could also ask your mom what the early teen years were like for her.
There are lots of bad jokes and good information about the emotional ups and downs of adult women during menopause. What a lot of folks don’t know is that adolescent girls go through much the same physical and emotional upheaval. The good news is that time does help. You will eventually grow out of this. In the meantime, get good information and take care of yourself. Be sure to get enough sleep. Eat right. Find a physical activity you enjoy. Good self-care usually lessens the effects of the hormonal and brain changes that are a natural, but sometimes difficult, part of growing up.
I wish you well.