I Have Suddenly Started To Lose Weight And Bruising Very Easily.sometimes I Don't Even Know That I Have A Bruise. What Can It Be? They Are Sort Of Yellow And Brown. Not Your Normal Black And Blue Bruises.

The bruise without any reason can be due to many internal problems which are

1. Leukemia
   
2. Coagulation disorders
3. Meningococcal infection
4. Certain types of cancers
5. Vitamin C deficiency
6. Long term use of steroids

In my opinion you have to visit a doctor for the further investigations as you are also having unexplained weight loss.