@Diana171
Because you have a few current hostings I am assuming you are talking about April's earnings, and not projected earnings! It should not be hard to spot any difference. As @Cynthia-and-Chris1 said, has there been any adjustments to any of those bookings? Has a guest applied for a reduction on a recent booking through the resolution centre? They can be somewhat tardy at letting hosts know when guests have been refunded.
Without the access that you have to your account details Diana, it is impossible for any of us to give you a reason for this reduction.
If you can't see anything through your transaction history and no reservation alterations have taken place or are pending, then you will have to contact ABB on +1-855-424-7262 / 1-855-4-AIRBNB (toll-free) and they will sort it out for you.
Cheers....Rob