Bike Route

I'm trying to get back into some physically exerting exercise. To start it off, I went on a 4 mile bike ride. I followed it up by a 2.5 mile run. Then, I did 600-700 yards in the pool (I lost track after about 300). It's like I did a triathlon. Throughout my workout, I felt my body was not up to it. I haven't pushed myself in the last two months. I'm going to do my best to keep it up.