Singing is all about sufficient air. Probably when you first wake up your voice is just not limbered up all the way yet.
Singing tips: Your voice is connected to your gut. Breathe from the gut. Stand up to sing. Good posture helps you to take in a full tank of air. Your voice is a muscle - it takes practice to strengthen and train your voice. Warm up your gut and voice by doing long tones and roller coasters (slide slowly way up and way down). Also, sing scales and intervals and vary the volume from very quiet to full tone.
Lots of water will keep your pipes healthy (caffeine is not good for your singing voice). If you smoke, quit. Find the range of tones that resonate in your head, throat, chest. Focus on producing clear steady tones - volume will come with increased control. Open your mouth and throat - you can't sing if your jaw is clenched shut. Learn to sing vowels and enunciate consonants.
"That darn Pythagorean Comma thing keeps messing me up!"
[url]http://en.wikipedia.org/wiki/Pythagorean_comma[/url]