It depends. When you say that "many of the losses were not counted" what do you mean? What matters in capital gains taxation is the "realization event" which usually occurs when you cash out. That can be even, a loss or a gain. If you had a realization, you can probably still use that loss for 2-3 years on your taxes. That said, you'd also have to pay capital gains on your gains when you realize those, which will at least be more favorable than income tax rates (for now). Your broker and accountant (both of which you should employ if you dabble in stocks) should be able to structure transfers in such a way as to avoid realization until you want to cash out. You can also use the money in certain kinds of retirement accounts and trade around without triggering taxes, so long as you don't actually move the money out of the account. But, if you take from those before retirement, they will tax you HARD.
FYI, I am an attorney (not a tax attorney), but this is NOT legal advice, just a friendly answer :) .