U probably have fibroids, I have them too. I used to have all those symptoms until I got on birth control . Now my period is lighter, and no blood clots. Talk to your ob/gyn about getting an ultrasound to see if u have fibroids though. a heavy period is the worst.
You do not say how old you are.
With you mentioning night sweats and a change in your monthly cycle, depending on your age, you may be starting the change of life.
Painful and clotting periods may mean that you may have Endometriosis.
You may find that cutting out all chunk, sugary and processed foods and fizzy drinks may help. As well as taking Evening Primrose Oil.
You can purchase diuretics specifically to help with bloating due to period problems from the large supermarkets (depending where you live) and also from the pharmacy.
Make an appointment to see your doctor and tell him of your symptoms. You will probably be referred to the ob/gyn, but the doctor can order blood tests to check your hormone levels and your iron levels.