bad work out days killing your vibe

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im in such a bummer mood, yesterdays workout was this first intense work out in about a month. I work out with a personal trainer, but a month ago i was hit by a drunk driver and lifting weights was a no go. Even carrying groceries hurt me...we continued working out but mainly cardio and yoga and resistance training to make sure my muscles didnt get lazy
anyways!
yesterday was my first back to normal workout, abs benching suicides step ups more suicides burpies PPFTTTTTT i was panting and dizzy like ive never worked a day in my life, but it felt good, you cant breathe but the breathing you get feels amazing!

BUT THEN he put me on the treadmill. This is when i lost it. I felt like such a fatty leaving there giving up at 12 minutes of pretty fast walking and going down to what MFP calls brisk walking lol
I think the anxiety just got to me, I could feel my legs turning to lead and saw the speed just going up and it scared the s**t out of me, i imagined falling in front of all these people, i imagined the guys in the free weights area laughing at me, it felt like high school!
i left feeling like such a suck =(

does anyone else feel like this after a vacation or time out?