Afraid not. Discounts cannot be combined and you can only use one coupon code or discount per order. This applies to discounted product bundles, sales, or any other situation where you see a discount applied to your total at checkout.
However! Your points code never expires, so you can simply save it to use on a future purchase.
Note: Gift cards are considered the same as cash, so you CAN stack your rewards points with a gift card!
Your points are tracked via your email address. Take a peek at your order receipt or the points notification email and make sure that the email address where you received those emails matches the one you're currently using to log in.
You may have multiple accounts under different email addresses, and your points are in a different account. 😉