Lightroom first displays a JPG preview that is embedded into the RAW file. After a few seconds, it can render the RAW using Lightroom's default settings, and thus the image appearance changes. There is no way to turn this off.
You can change the defaults, or apply a develop preset at import, to get the photos to look more pleasing right away.
With regards to your statement "The images i have now i can not use", you need to use Lightroom to edit the photos to the appearance you like.
Regarding this last shoot, did you shoot raw as opposed to perhaps normally shooting JPEG?
NO. I shot my las shoot raw and almost always do unless the images are not for work. This is the third time this issue has come up yet i shoot raw all the time.
First thing to do is to change the default camera profile applied in Lightroom to camera standard (assuming that you shoot Canon or Nikon). Also make sure that your camera is NOT set up to use any of the HDR modes. Nikon calls those Active Dynamic Lighting. On Canons you often see things like highlight priority mode or "Auto Lighting Optimizer". Make sure that the picture style is set to standard and that for newer Canons the HDR mode is turned off. Most of the HDR modes simply underexpose the image and then add an instruction in the raw file to compensate for this to prevent highlights from being blown out. This causes more noise in the shadows and if you know what you are doing there is no point to this as you should simply expose correctly and get the highest quality raw.
Lastly, make sure that in Lightroom you have not checked "Apply Auto Tone Adjustments" in Preferences->Presets. This should make the default rendering of the raw files the same as the in-camera jpeg (what the camera shows on the back even if you shoot raw) but still give you all the latitude of raw files.