Hello!

I rescued an eastern grey squirrel 2 days ago. He is about 4-5 weeks old, taking formula really well (on puppy formula, his fox valley comes in the mail tmw)

He pees a little, but has not pooped since I rescued him on Wednesday. His pee now smells like fish, and he appears to be uncomfortable.

For the constipation, I have 2ml of pedialite about 30 mins ago.

I have a pill amoxicillin 500mg (my old prescription) and I have clindamycin HCL that was prescribed for my dog (it’s expired by 3 months).
Can I use any of these prescriptions for him? If not, what should I do?