You say you are having trouble "speaking up." Here is a simple suggestion:
*When you want to say something, but you feel shy to speak out, begin with what I call a SILENT HUM. You pick a note and hum it in your head, silently, without voicing it. Then start talking and say say what you have in mind. If you are able to step away from the other person or group, then go to another room or another space and HUM aloud before you return to speak your piece.
Practice this technique with your friends or family to become "easy" with it. In no time, you will FIND YOUR VOICE.
Good luck, and let me know how you like the SILENT HUM.
Dr. Joan's Harmony Key: A well-spoken word is like honey in the mouth.