Go and see your GP. It wasn't a heart attack but it was a wake up call and I don't think jumping to seeing a cardiologist will be that helpful, although a GP can refer you on if they think you need it.

I was in the foothills of heart health problems - high BP, cholesterol creeping up, etc. and the health staff were starting to express concern (suggesting I might need to go on statins). So I turned it around in two years and at my last health check my weight and bloods were all "perfect" according to the nurse. So it is doable.

However, from what you say, mental health issues may be holding you back and making important and sweeping changes to your lifestyle require effort and focus. So the GP may want to get this addressed while starting to monitor your health through regular checks. I found the checks motivating in themselves as the data can really prod you into action because you no longer can say you are probably unhealthy - it is there in stark numbers. I also suspect I was slightly gamifying it as I made beating the numbers a focus and figuring out what I needed to do to adjust each on (as lowering triglyceride levels requires different action to lowering LDL, bad cholesterol). I even made a spreadsheet.