What Causes Dizziness And Weakness After Having An Abortion?

i am 36 years old female. got married 2 years ago. i am a very very active energetic individual. After marriage there is too much stress in life as i need to take care of my aging/ailing parents inlaw who also have a very demanding nature. my husband is very caring and cooperative but obviously i do understand the responsibility i have. 4 months ago i also had a miscarriage after 11 weeks of pregnancy. After all this sometimes i feel weak and dizzy. This morning i decided to exercise after a long time and after that i felt very dizzy and weak and lied down. Once my heart rate became normal i felt better. I do skip lunch most of the times. is there anything serious or i need some advise?