My people! :p
I'm like this too, although I've gotten better at holding back the tears when I need to (e.g. at work). But yes, sappy commercials, heartwarming baby or puppy videos, feelgood FB posts, etc. - I can't help it.
My go-to tricks are looking up (seems to stem the flow if you do it right away), biting my lip, and mental distraction.
That said, it's a funeral. Let the tears flow. :grouphug: