New and looking for support

Hello,

I'm new here and looking for some support. I'm not new, however, to trying to lose weight. If I'm honest, I haven't had the will power to stick to much and have been in some serious denial about my weight and the health effects it's starting to have. I though my at 36, I am still young enough to be at a lower risk for heart issues and so on but last week, while I was at work, I watched on as a 30 year old woman walking through the foyer fell over and died. She was obese and I am of the strong assumption that she had a heart attack. It was a serious reality check.
Now whenever my arm aches or I have any chest pain, I have flashbacks to the paramedics shocking her body and performing CPR (which if you've never seen, is very violent in nature).
I'm a secretary and spend most of my day at a desk. I like the vegan lifestyle and the food looks delicious (I buy a lot of plant based cookbooks) but I end up eating pizza, fast food and junk more often than I'd like to admit.
I have anxiety and high functioning depression where I can work and live but I don't often enjoy my days.
Anyway, this is a long winded way of saying I want and need help and support because this time I want to be successful in getting healthy.
I'm 5'4 and this morning weighed at my highest ever weight of 177.6 lbs :( - I've had two full term pregnancies and have never been this heavy. My body aches and I'm tired all the time.
Is there anyone out there with some kind words or advice? I need both! Thanks for reading!

Rebecca