Here is was I suggest and it’s probably the best advice I can give you:
-Get checked by your physician for any medical/health issues (if any).
-Hire an experienced trainer to help you and also guide you with an efficient and constructive way by designing a fitness program that is specifically for you.
-Get a meeting with a Registered Dietitian to help you with your diet because a fitness program alone is not enough. Your diet could also be part of your current issues (although it’s hard for me to tell from the information which you have provided).
I hope this helps and good luck to you.