Are the dried blood and clots coming from the vagina/uterus, and you just notice them when you go to the bathroom, or are they coming from your urine itself? These are 2 different problems.
It seems to me to be highly unusual to still have blood or clots in the uterus - I think you should check out whether the entire placenta did not come out and you have some retained tissue, with or without infection. Get another check-up, or another opinion from another doctor. If there is blood in the urine, that is a different problem and you need a urinalysis and possibly a visit to a urologist.
After 3 months, "Keep an eye on it" seems too cavalier and casual. Insist on more follow-up.