I can only address my husband's experience and with only one form of chemo. My husband had six rounds of docetaxel chemo years ago. His side effects followed a familiar pattern: he felt energetic and good the first day or two after the chemo because of the steroids he got with his infusion to minimize immediate side effects. Then he felt exhausted the rest of week one, but no nausea or vomiting or other GI symptoms. Week Two he felt progressively better than during week one, and in Week Three, he felt increasingly good and pretty normal--just in time for the next round of chemo to be given. The chemo really knocked the PSA down and the cancer back, as revealed by scans, and it kept the cancer suppressed for some time. So for us, chemo was absolutely the right thing to do as soon as it was recommended by Dr. Kwon at Mayo Rochester and by his local oncologist at Simon Cancer Center in Indianapolis.

NOTE: Something to watch for--my husband's white blood cell count plummeted after the first week of chemo, and he was given a medication to build his white blood cells back up to normal levels. Apparently this is pretty common, both the white blood cells tanking after a chemo infusion and the use of Neulasta when it occurs. After it happened to hm, my husband was given a Neulasta OnPro device by the infusion nurses to wear on his upper arm for about 27 hours after each subsequent chemo infusion. At about the 27-hour mark after chemo is given, the device injects the medication directly into the patient and then you simply remove it from the upper arm and discard it as medical waste. There was no real pain, just a prick, when the device injected the medication, and it did not hurt at all when I removed it from my husband's arm.
I hope this helps reassure the original poster and anyone else concerned about having chemo, and also reminds everyone to watch out for the effects of docetaxel on the white blood cell count. I should say that I don't know if other chemotherapy drugs have the same effect.