ABSOLUTELY you need to be SEEN by a OB/GYN immediately! When you have a conern that's big enough for you to be writing here- then a trip to the gyn is never wrong!!!
PLEASE promise you have already gone or you are going!!! At the very least, contact your GYN and talk to the nurse.
Like someone else said, any clot bigger than a quarter is a "RED FLAG" (they didn't say that about the red flag, but I think it's what they meant)
I hope you have sought help- even if it has resolved. There are cases where women have had to have a hysterectomy, or worse, because they are bleeding out and they don't know it.
The OTHER RED FLAG (pardon the pun, just realized what I said about RED)- is if you soak through more than two pads per hour- you must call your doctor!
Good luck- let us know how you are doing!
If they are bigger than a quarter yes, you need to go to the doctors. Shedding of blood could mean you are missing a hormone called progesterone. Talk with your doctor, you probably will have low iron and Armenia from so much blood shed. Hope you get better!