Unexplained Bruising and Weight Loss

So this has more medical question, and i wont take it to heart with suggestions. but I'm known to bruise easily but usually after like 2-4 days its gone. but I've had this bruise on my upper right arm for about a week and 5 days without any fading look since i found it odd so i remembered when i saw it. then today i saw on my left arm this bruise that in a way looks like someone grabbed me hard like theres finger marks but i know for a fact nobody has touched me there so i dont know how i got it. but adding on symptoms, I've been very fatigue, feeling weak, and unexplained weight loss, like i lost 6 pounds in 3 days as ive had this happen before where my weight drops even if im eating alot so i have calorie drinks (Boost) to make up for any nutrients im missing due to my less frequent eating. I'm not sure what is causing these symptoms so i suppose I'm asking opinions of what it could be so i can narrow down to certain issues so itll be alot of a less stressful experience at the doctors as i dont feel like its normal for me at all. anything will help