How to differentiate between depression and daily anxiety? I'm not sure what is with me

Feeling loneliness, always sad, tiered and have no wellness to do any simple thing, I think they are signs of depression, any can help me?

I don't cry often and it used to be hard for me to cry in the saddest situations but now i cry everytime i think of anything bad happened even if i'm in public ( i used to hate that)

My parents divorced and i stayed with my mom but then she got married again and had a son. Since then she gave him all her attention and i became invisible in the house. She would not ask me about what's going on with me anymore, she don't even care about my education. I've been feeling really bad and it's like i'm stranger living with this family. Even though her husband is a cool guy but i just want my moms love. I feel so lonely and i can't talk about this with my relatives.

Last year i used to have the best grades and scores in my class, even tho i didn't study that much but i always had an excellent grade. This year i started studying and working really hard because it's my senior year, but somehow i'm having the worst grades in the class and i was considered by the teachers and my classmates as the failure of the class. I didn't even tell my family about because they know that i'm trying hard,so i don't want to disappoint them. I'm starting to get really anxious, stressed and nervous about it to the extent of having sleeping problems and having nightmares. I'm slowly going through depression so i don't what should i do to fix this.