Translation:I was amused yesterday.
What about "I had fun yesterday"?
This seems more reasonable, otherwise the sentence makes no sense out of context.
That would be Мені було весело вчора.
"I was funny yesterday"?
That would be "Я був смішним учора" ("I was funny", as in, I made good jokes, or, I looked funny the way I behaved or was dressed, people found me funny)