Bleeding for that long...especially since you indicated that some of it has been bright red blood...is dangerous! You might need to have a D&C to clear out excessive endometrial tissue in your uterus.
Yes...there are specific tests to check your hormone levels...very surprised that your doctor did not do them. There are saliva tests to check levels...but the blood tests are more accurate.
Find another doctor who will take you more seriously and get the bleeding under control. Then read through the info on this site about Liver Cleansing and do a series of Liver Flushes to help bring your hormones back into balance.