High blood pressure

Alhamdulillah after 6 good months of staying at home, I am finally being called to serve for the nation as an English teacher. I sincerely hope my new school would assign me to teach only English or minor subjects, not other critical subjects. Apart from that, I am stuck with my medical check-up. Doctor detects that my blood pressure is a bit too high and twice I went to check, it only gets higher. MAy Allah protect me. I need to change my lifestyle now and start exercising. Doc gives me another week to start fitness activities and control what I'm eating and check my blood pressure with her again. Honestly I don't know where to start when it comes to fitness. Doc said I hafta start with light activities like walking cause I'm considered obese and my body can't support my excessive weight. Need your prayers and support, thank you peeps