Sorry to hear about your symptoms - I can see that my colleagues, Drs Gan and Nandakumar, have both added quite a lot of information already., but perhaps I could add something from a Sports Medicine perspective?
Usually, its advisable to make changes in small steps - either with your physical activity levels first or your diet. Doing too much too soon might well be a significant contributor to your symptoms - in addition your current menstrual period. Speaking of your periods, if you do endure heavy, prolonged and painful menses - as with many young women I have met in my career - it might be worth seeking advice from a gynecologist and consider something like to contraceptive pill to regulate your menstrual cycle. This in turn might stem the losses each month and hence help your symptoms.
I believe in an earlier post I discussed about diet and how this can affect liver function, and there was another about how you can try to bulk up.
While I know both are not immediately relevant to your symptoms, there is some information about healthy eating that I gleaned from my Sports Dietician colleague. Essentially, our bodies need a balance of nutrients and not all calories are equal. Some come from more healthy sources than others. Perhaps in your case it would be good to visit a dietician with an interest in sports/physical activity and discuss your goals.
Equally, if you would like more advice about exercising safely and perhaps considering potential pitfalls before t might I suggest a Pre-Participation Screening? This involves a thorough medical assessment, various investigations and a discussion on your health/fitness goals. It might be a good starting point before you progress further!
Hope things go well.
BW
Dr Dinesh