Chronic halitosis girl

I'm new here so please forgive me if I do anything wrong. I'll try to keep it as short as possible. I just looking for tips and I have a few questions as well. Sorry if this is too long :/

I'm an 18 year old female living with chronic halitosis. I've had BB since elementary school. First time I became aware was in the 4th grade. This was around the time I started struggling with low self-esteem and developed depression which played a huge part in me not taking very good care of my hygiene all together. 

Anyways, long story short, I'm depressed today, I have severe social anxiety and Ive been sitting in my home for the past 3 years straight. This has held me back from taking a critical trip to the dentist. I did fail to brush throughly since the 4th grade (to be more specific, I wasnt brushing twice a day or brushing the back of my tongue). I probaly spent 1  minute at the most on my teeth a day and thats it. During the three years Ive been sitting at home, I rarely brushed and it was never thoroughly.

I recently started researching ways to cure my BB. I realized that I do have post nasal drip and Im also a mouth breather. I did have dry mouth prior to me starting to brush more often and drinking more water. I don't think I have tonsil stones because I haven't spotted one yet (if that means anything). 

I will say I haven't been brushing consistent due to laziness and feeling like I'm wasting my time. The most consistant I was was for about 4 days. I do plan on being consistent this year though. I smell the bacteria at the back of my tongue, my throat and under what feels like a flap at the back of my roof. I think that is where the mucus from my nasal drip comes from, IDK. I should note that I smell sort of.. I think a maybe bleachy smell I guess... That's the best I can describe it.

 I recently purchased a TUNG brush, tongue scaper and my mom got me some biotene. I also have a manual toothbrush and automatic. When I did brush it wasn't organized but I did spend 1 minute on each section of my teeth and I brush kinda hard. Did a lot of scraping with plastic spoons and lots of hawk spitting. I'd have to blow my nose a few times during oral care. I'd spend about 35-40 min total every time. 

Now for some questions.

1. What's the best mouthwash and toothpaste for people with chronic halitosis? (My mom recently purchased biotene and I started using my little brothers bubble gum flavored crest cavity toothpaste because the minty kinds make me nauseous. Thoughts?)

2. Should I try a leafy green/ vegan diet? (Spinach, cucumber, celery, apples, water, green tea?)

3. Best toothpaste?

Thanks for reading if you've made it this far.