help me please i feel so alone!?!?!?

What i mean is well i cant explain proper title for this but ill try too explain what i mean i am 15 and in year 11 I was told by the doctor that she thinks i might have anxiety.

Well when people stare at be or look at me i think they don't like me or i have done something wrong and i often think people talk about me and when im in lessons i never think i can do well i either think i will fail or just do average i never feel as i can do as well as others , i cry quite a bit too sometimes even saying goodnight to my mum ends up making me cry when i leave her room, when i read texts if they don't have a " x" or if they have a full stop i feel as if the person is annoyed at me and when my family go out i worry that they will get hurt or will be in trouble so i often ring them or texted them if i don't get i reply I worry more , If my mum goes to her friends over the road i text her to make sure she has keys and stuff to get in the house or i can't sleep i even will text her friend if my mum doesn't reply my mum says i treat her as if i'm her mum sometimes i will feel empty like i don't want to do anything or really feel anything i will just lay there on my bed with a blank face playing my ipod or phone but i don't get any enjoyment out of it , Some days the littlest thing will make me angry I often lose my temper with my sister the most of the time and i will shake or cry i mostly end up crying, I used to get so annoyed i used to sit there drawing people with cuts on there face and stuff but i don't do that really anymore but I do sit there when I feel down i wonder how my family would feel if i was gone and would it be better for them then i end up crying at these thoughts.

Now I am going to tell you somthing that know one knows because i feel REALLY embarrassed about it none of my family know but basically i have this big teddy and I have to sleep with it every night and if i stay at a mates i will take my smaller one but the thing none knows is why i always sleep with it , When i have my teddy i will make up a little story in my head and I will always have they teddy cuddling me and i will lay my head on it instead of the pillow sometimes i think it will protect me if someone broke in the house or hurt anyone at night.

I often worry that someone will try to break into the house or something.

I cry myself to sleep sometimes and I feel that theres always someone watching me from somewhere so i don't do anything that might embarrass me.

One day last week I was at school and I began to cry because i wanted my mum so i started texting her that i wanted to come home but i had to stay at school only texting her made me happy that day . I am crying whilst typing this i don't know what else to add but if i need to i will add details. I just want to know if this is normal or a little strange.

thanks in advance

Please help

Ps : when i worry by stomach will really hurt and can sometimes cause me to have diarrhea (so embarrassed). I also often feel fat and ugly.