Talk to General Physician on Weakness In Body

Hello dr. Im 31 years old. I have a baby of 1 yr old. I also breastfeed him on his demand. My prob is im feeling weak since few days. My sleeping routine is also disturb these days due to my baby as i breastfeed him in demand. Since few days i feel lazy during night time like from the evening i feel like my eyes r getting heavy and sleepy plus i feel blurry vision when i take off my glasses and sometimes i feel like im getting unconscious but this feeling of conscious is only of 1 sec and then it gets normal. I also feel light headache. Kindly suggest me which test should be done to evaluate the problem.