Hi,
Welcome to ehealthforum.
If you are with known heart problem, then having a baby might be risky for you. Visit your heart doctor and diabetes doctor and discuss about your pregnancy plans to see if any risk is involved.
Your irregular periods could be due to anovulatory cycles (without egg release from ovary) which are common in your age. Once you start having ovulation (egg release from ovary) regularly, your periods will also be regular. Wait and watch, do not be hasty. Your increased weight along with irregular periods could also indicate possibility of PCOD. Concentrate on your health. Make sure you have a good diet to be able to support pregnancy, as with weight issues (your BMI is coming 39 with the values you have given for height and weight, which shows that you are obese), and heart problems, and diabetes you stand chances of having miscarriage and complications with your pregnancy (if you get pregnant). Visit your gynecologist for further evaluation for irregular periods and PCOD to start with treatment to reduce weight, induce ovulation and to help you conceive.
Take care.