Wedding gift advice!!! HELP!!

So my cousins wedding is today and we aren't sure we should give a gift. She didn't buy me a shower gift or give anything when her and her fiancé attended our wedding. I spent $100 on a gift for her shower already. Not sure I should give an additional $200 when she didn't give us a thing!?!?
What does everyone think I should do!?!? I feel cheap and rude showing up to a wedding and not giving anything!