How do I get over embarrassment after sending letter to police?

I sent a thank you letter to the police officers who saved my life that was too long, not formal, kinda sentimental, and pretty quirky. They know I have a mental illness, but I’m so embarrassed I didn’t make it more proper!

I’m devastated I blew my chance to thank these guys in the most respectful way possible. How can I get over this?

Do I need to apologize for being informal?