Out of breath easily?

So I'm 5 weeks and 6 days. Before I found out I could run a mile every day easily, but now I'm completely winded after a quarter of a mile. I'm not even pushing myself that hard. Even after walking at a brisk pace makes me feel like I'm out of breath. I've been trying to do lunges, squats, etc. but I have to take lots of breaks because my heart just starts beating so hard and so fast that I'm wondering if I should be working out at all? Is this normal? What can I do?