Today

Hello. Like I wrote yesterday, today I went jogging with my dog. I am so tired and my feet hurt. I think that the shoes I used weren't the appropriate. There were too many different kinds of dogs. And I met a dog who was the same race as mine... Weimaraner. We are so tired, I am going to take a rest.

Joining complete sentences with commas is a stylistic, informal technique. It's fine as long as you know the proper way. Good luck with your studies--and your dog!