Trying to get my life together...any advice?

Not sure where to begin, but I am 17 years old no friends. A drop out. and kind of socially inept as you can imagine being someone who stays home all the time. I am not here to fully focus on my issues. I am just looking for some kind words I guess on my path. I made a New Year's resolution this year and I really plan to accomplish everything on the list. No matter how hard or how much it sucks. My list is something along the lines of...

1. Losing weight, I have been watching my diet. and exercising when I have the motivation.

2.Getting my GED

3. Getting a Job

4.Reading 3 books a month

5. Really learning the meaning of Self love

Nothing really too challenging although I am weary that all the stress I get from anxiety probably raises my cortisol levels. Causing me to gain weight instead of lose weight. But never mind that,

May not sound like it because I am really depressed at the moment. But I am really determined to put a check mark next to all of those things on the list. To show myself I am not useless.

My brother has been helping me in the job search process, we have been looking for things that don't really require too much customer interaction. Leaning towards retail and grocery stores. seeing as I am a dropout with minimal skills. Mindset is fast food or retail. But unfortunately alot of positions like stocking the backroom or aisles aren't available. I had a job interview at Mariano's on the 23rd and I completely bombed the interview couldn't put words together. Only positive for me is I didn't have trouble keeping eye contact like I thought I would have. The interviewer would ask me a question and my mind would go comepletely blank. Despite this, They still wanted to hire me in Hot foods department where I think I'd pretty much be cooking and cleaning dishes. basically little restaurant within a store. So very customer orientated. So I got the job but I feel this overwhelming amount of guilt and shame come over me after that job interview. I thought that I would be happy to put a check mark on my LIST but I just felt so ****** about myself. I still haven't been able to pin point why that is. Could be I didn't get the position I initially wanted. Anyways fast forward to today the 28th. I have an interview at Sam's Club for a Freezer/cooler/deli position on Feb. 1st My birthday. First why does it have 3 roles in one job title. I looked up what it is like to work in the freezer/cooler position and you pretty much do a bunch of stocking of frozen products. I think the walmart website described it as something along the line of It's like being paid to go to the gym. Which sounds very appealing to me, because it would help knock out 2 birds with one stone. So I guess to get to the point...

Does anyone have any job interview tips for someone with an anxiety disorder off of meds?
Also any tips for tackling adult hood when you feel so crippled mentally as a human being?

and the last one probably most importantly. I don't know If I am alone in this but sometimes I get so much anxiety and builds up day after day after day. And develops into what I would describe as clinical depression. Used to think I had to depression but I have come to the realization that my depression has always been a subset of my anxiety. and this very moment. What I've described is very real for me at the moment. No motivation to get up in the morning. thoughts of ending it all. You know, any little task feels like running a marathon. And I have a job interview Saturday. It's not just the interview either, like how is someone like me going to be able hold down a job? Any advice would be really appreciated. I guess I am just really afraid of failure. I don't know.