My 8 week old baby doesn't sleep. HELP!?

Since my daughter was about 3 weeks old she has never slept during the day and barely at night. For the most part she is awake from anywhere around 12-17 hours a day. At night she will sleep for 6-8 hours at best waking once to feed. During the day she will not sleep no matter what I do. I have tried putting her in a dark room, playing lullabies, increasing her formula around naptimes, stroller, swing, car rides, sling, etc and she will not sleep for longer than 15 minutes and wakes up tired and fussy. Not to mention it takes me around 2 hours to get her to fall asleep in the first place. I have also tried putting her to bed while she is still awake but she will scream forever until I go in and get her and I've tried waiting until she's in a deep sleep and she wakes up as soon as I put her down. I am so out of ideas and need some advice!!!! I know she is tired because she is fussy and miserable all day long and needs to nap. Her doctor says she is gaining weight and is otherwise healthy. She switched to Soy formula about 3 weeks ago and is doing really well on it so I know it's not that. She won't even sleep with me in bed!!! Even just to hear that other parents are having this problem would make me feel less of a horrible mother... What do I do to get her to sleep and be more content???