Yes, that is what a heat cycle is...this is when they are fertile for breeding...so keep the pup away completely from any intact males. The bleeding will start lightly, then get heavier, before lightening up once again and stopping. Start to finish is 3-4 weeks. For safety, plan to keep her away from all males for the next month.
Life isn't about waiting for the storm to pass. It is about learning to dance in the rain.