Well, for a female at this age, I must be very very suspicious of a urinary tract infection. However! To get the infection, at this age, there is often a underlying predisposing condition like kidney disease or hypethyroidism (elevated thyroid hormone) that causes the urine to be more dilute and get the subsequent infection.
So, without question, I believe this is well worth a vet visit and I would go today.
Another differential would be idiopathic cystitis. This is a sudden onset of inflammation inside the bladder that we believe can be stress-induced and is common. It is not due to stones, infection, cancer, etc...But, at 10 years of age, the consideration for infection goes higher on the list.
A basic blood and urine test can answer many of these questions. Plus, with the spotting blood, I know Mama is uncomfortable. The vet will likely start pain medication immediately.
Hope that information helps