My urine has been dark and/or cloudy for around 8 weeks. My urine sample showed traces of blood and protein. Should I worry?

Get checked out. It would be wise to have a formal evaluation given the above description to identify any possible injury to the kidney. A nephrologist is a type of doctor who deals with medical diseases of the kidney and can initiate a workup and refer you to other specialists as needed. Alternatively speak to your primary doctor for advice and/or referral.
See your doctor! I wouldn't worry - i would see my doctor! worry is not going to help. Seeing your doctor and having further testing will help show what, if anything, is wrong. And, yes, it could be serious! see your doctor!