Hello. Recently I Have Been Having A Problem While Walking

Hello. Recently I have been having a problem while walking around my home and doing daily things. This problem happened just today as I was walking in the hallway of my house. I had sudden dizziness and my posture sagged. This has occurred many times, and has happened more frequently. The worst has been when I suddenly fainted while in the shower. Another problem has been that when falling asleep, it seems that I stay awake until farther in the night. Though that may be because of habit. Please help!