It is normal up to a point, and you're still within the three-month window when the surgeon said it was to be expected, so don't panic. It's possible to damage something *slightly,* too - these are still new, delicate, healing tissues, and a small scrape will bleed a lot more than you'd expect.
The other thing I learned? Lube mixed with blood will look like a LOT. It also makes it hard to tell when the bleeding has stopped, b/c I was easily leaking lube after a dilation for at least 3-4 hours, and if there was some blood mixed in during the session that would be coming out too.
You can call your surgeon or a local doctor for peace of mind, but in the meantime try not to worry too much. Lack of pain and not very much blood (or what there is, either dark red/clotted or frothy/pinkish [that'd be the lube]) likely means it's not serious.