People with Weak D will often be labeled as D positive when donating blood, and D negative when receiving blood, although the D negative label is more precautionary than it is necessary, and most people with Weak D can receive both positive and negative blood without issue. If you choose to donate blood, it will be labeled D positive, and treated the same as all other D positive blood.
To answer your second question, yes! Donate as often as you can. There should be no problems associated with you donating blood. There can sometimes be confusion as to what to label a Weak D donation, but it should not effect a blood transfusion in any way, as there are multiple checks and screens to ensure that both blood types are compatible before a transfusion takes place.
