The simple answer is that there is a huge difference between these two observances. One is a biblically sanctioned festival of God; the other is a man-made festival without biblical authorization. One teaches us how to live godly lives; the other masks this important truth.
The Days of Unleavened Bread, commanded by God (Leviticus 23:6 Leviticus 23:6And on the fifteenth day of the same month is the feast of unleavened bread to the LORD: seven days you must eat unleavened bread.
American King James Version×) and observed by the early Christians (1 Corinthians 5:6-8 1 Corinthians 5:6-8  Your glorying is not good. Know you not that a little leaven leavens the whole lump?  Purge out therefore the old leaven, that you may be a new lump, as you are unleavened. For even Christ our passover is sacrificed for us:  Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth.
American King James Version×), teach us to put sin (represented by leavened items such as bread and cake) out of our lives. This festival teaches us that we must overcome sin with the help of God's Spirit and live righteously.
Easter, in contrast to the Days of Unleavened Bread, not only lacks biblical authorization but was instituted by men who deliberately replaced God's commanded festival with one derived from paganism to make Christianity more accommodating to converts who wanted to hold on to pagan traditions. In doing so, they imposed on this festival a Christian meaning—to celebrate Christ's resurrection.
As wonderful as Christ's resurrection is, the Bible specifically tells us to annually commemorate His death, which we do in the annual Passover observance (Luke 22:19 Luke 22:19And he took bread, and gave thanks, and broke it, and gave to them, saying, This is my body which is given for you: this do in remembrance of me.
American King James Version×; 1 Corinthians 11:24-25 1 Corinthians 11:24-25  And when he had given thanks, he broke it, and said, Take, eat: this is my body, which is broken for you: this do in remembrance of me.  After the same manner also he took the cup, when he had supped, saying, This cup is the new testament in my blood: this do you, as oft as you drink it, in remembrance of me.
American King James Version×), but it does not give the same instruction about His resurrection. We do essentially commemorate Jesus' resurrection, though, in the commanded festival of God during which it happened—the Days of Unleavened Bread. His resurrection is crucial to the plan of God and the process of leading us out of sin. Indeed, we must progress beyond the fact that Jesus was raised to following our living Lord in the way we live our lives.
By the way, where do you read about using rabbits and Easter eggs to remember Christ's resurrection in the Bible? Answer: Nowhere.
Given the history of Easter, it is quite understandable why so many people today think of Christianity as only a celebration of what Christ has done for us instead of the honorable quest to live godly lives. If you want all the facts, read our free Bible Study aid booklet Holidays or Holy Days: Does It Matter Which Days We Observe?