Out of breath! I'll be 8 weeks tomorrow and because I live in nyc, I do tons of walking at a fast…

Out of breath!

I'll be 8 weeks tomorrow and because I live in nyc, I do tons of walking at a fast pace and never noticed feeling tired by it. The past few weeks though, it is very hard just walking 10min to the office and I am out of breath fast. I feel like I weigh 300lbs instead of my 130 because of the effort it takes me! Is this normal or something I should speak to my OB about?