How to maximize survival chances if falling into lake?

Sorry if the subject is out of topic. Just out of curiosity what would you advise in the following scenarios. These are imaginary just for educational purposes on the survival capacities. Question 1: I fall in the lake. I am still wearing my winter clothes and shoes. Let assume that I am not wearing a personal flotation device (PFD). Shoreline is 5 km away. What should I do to maximize my chances of survival? Question 2: Same as Q1 but this time I wear a PFD. My fitness level is enough to allow me to swim 5km in a swimming pool. I swim 3 times / week with an average distance of 1.5 km. Although I had never tried to swim 5K non stop. But if my life is threaten, I hope I will be able to make it. Thanks in advance for any help.