Hi, timbo

My main protein sources are:
- cheese >150 g/day
- cashew nuts

Both are about 25%(wt) protein, cashew nuts are even said to contain vitamin B which are hard to find without meat.

Other high protein (~25%) vegetarian food:
eggs, nuts, lentils, soy, tofu, split pea...

Less proteins:
beans, chickpea, milk...

No need for supplements. Keep your nutrition as natural as possible. Avoid artificial sweeteners, colorants, preservatives etc.

Most important: Do not change a diet abruptly. Maybe even re-introduce some small amount of meat (e.g. two meals per week) and reduce progressively.

Eric's tip for the salt will be good for reducing your blood pressure. Also, reduce progressively until optimum. Too few salt is bad, too.

And as always, drink huge lots of water. From time to time, you may want to mix your own isotonic drink to re-establish osmotic pressure (feeling too much water in your stomach):
50% orange juice, 50% water, some sugar, some salt

Good luck