A bear market is nothing to worry about at your age.
If you buy investments, and they go down, and you are raking in cash by the bucketload as you claim, then you simply buy more as stocks go down.
As many stocks decrease in value, the dividends they generate don't. Therefore, the yield is effectively higher on these stocks the cheaper you are able to get them at. As stocks go down, you buy more if them each time you contribute, and each dollar effectively earns you more provided the yields don't get dinged by the recession. Even if they do, however, you will end up purchasing more shares as the stock price goes down, so when things recover and the price begins to appreciate again, the dividends will grow again, and not only that, you will own more shares when they do appreciate making your investments more valuable.
The same holds true when you invest in indexes.
Try not to look at your investments from the standpoint of what they are worth. Try to look at them from the standpoint of how much annual income they generate for you, and what this yield is based on the value of the account. This somewhat contrarian way of looking at things will help you do as Warren Buffett recommends in classic value investing - be greedy when others are fearful, and be fearful when others are greedy. Of course, look at this in aggregate, and don't chase individual investments strictly because of high yield - be sure whatever you are buying is fundamentally sound first.
The key is saving a significant enough portion of your earnings (as you seem to be) that an economic downturn will allow you to go nuts buying things on the cheap (it's an opportunity, after all), while continuing to contribute even when valuations are stretched, because predicting a market top is too difficult to spend energy on, especially since you'll probably get it wrong anyway (as will most others who try).