All of the symptoms you have described could be attributed to anemia. If you were feeling otherwise normal before donating, then it is most likely limited to the loss in blood volume and oxygen-carrying red blood cells. It sounds like you might have been somewhat borderline before you donated, and now your body needs longer to recover than you used to need in the past.
When I've been at my lowest iron levels, I wouldn't be able to ride for about a week after my period (I have heavy menstrual losses). For someone who has good iron levels, losing a lot of blood (period, donation, surgery, etc) can be easily recovered from within a few days. If your iron stores are low or depleted, it can take weeks or months to feel back to full strength depending on how much blood you lost.
Talk to your doctor and get your iron (ferritin) tested. If your levels are low (below 25) or borderline low (25-45) then go ahead and add some iron supplements and get retested in 6 months. In the meantime, stay well hydrated, and eat lots of iron-rich foods. Meat, especially organ meats like liver (yeah :eek: I know!) contain the most available absorbable form of iron. Vegetable sources like legumes, spinach, etc. are also good but not as bioavailable.

