Depending on where you live- you might be able to use a local walking trail during the day time when it's not busy. The weather is ideal for walking- but I completely understand the anxiety that comes when you think that people are comparing themselves against you.
Try to do baby steps- start parking further away when you go to run errands; give yourself a reward for going to the gym (e.g., let yourself see you favorite movie); read-up about birds / flowers local to your area and do nature walks where you just focus on identifying the species.
Good luck!