I Don't Understand

I woke up this morning feeling fine. I went to the dentist and then decided to take some special little ones out to the movies. Somewhere between this time my insides began to twist. I fought the feelings and tried to ignore them. This cannot be happening again. I have felt so much better the past week and a half. I do not want to feel so down again. I don't know how this creeps up on me. It isn't fair. I tried to focus on other things. You would think that being around people that love you would make you feel good. Just the opposite. I feel incredibly alone. I am alone in my head and my thoughts. All i want to do is run. Run to my bed and turn out the lights. I don't want to see or talk to anyone right now. I feel like a terrible person. I want to be there for my friends and others, but I just can't. I can't force myself to feel happy or be bubbly. All I can do is sit quietly and try to grin and smile when it looks like an appropriate time too. This only make me feel worse because I feel like a failure. If I try to move or talk I will bust into tears. I want to leave, but I don't want it to seem like I don't care enough to spend time with them. I can feel my heart pumping. I feel incredibly trapped; physically and emotionally. It has gotten worse and I can barely focus. My eyes are blurred and my breaths are shorter. I fucking hate this! Why do my emotions have control of me. I didn't choose to feel like this today. I don't know what is different about right now then what was happening yesterday or the day before. And I hate where my head goes. I don't want to live like this. This is the worst darkest loneliest feeling ever.