Is this a pet rat?

Found this little guy on my walk home, it quite literally jumped out of the grass at me in a residential area. I have a couple pet rats and have had some through out my life and instantly assumed it looked like a pet rat. It isn't very scared of humans more just scared in general. Little guy seems sick and barely eats and drinks (but definitely does a little bit).

I am wondering if this is a pet and what can I do to help it? I am scared of it getting me, my rats, my cats, or my girlfriend sick but I feel as though it was asking for help and obviously needs it based on its body language and energy. What should I do?

PS: I am poor and unaware of a local vet or rescue (I also don't have a car as I live downtown)