I'm very sorry to hear of your situation.
Yes, you may sue, going back as far as 3 years for all the unpaid wages relating to your lunch breaks that you were forced to work for. Under CA law, if you work no more that 12 hours in a day, you can legally have a written agreement with your employer to waive your second meal break---but you still must be paid for the time you do work. Here is the law regarding the ability to waive the second meal break of the day:
As for the suit against the employer for failing to pay you for the working meal break, you may file suit and seek not only the back pay for up to 3 years prior to the date that you actually file the suit (you cannot go back further than 3 years under the law), but you may also collect what is known as liquidated damages.
Under federal laws (FLSA), you are also entitled to what is called Liquidated damages. Liquidated damages is equal to the amount of back wages that they owe you and must be paid in addition to the wages themselves---so you essentially get double wages in the claim based on their willful failure to pay you. http://labor-employment-law.lawyers.com/wage-and-hour-law/Liquidated-Damages-and-FLSA-Claims.html
Here is an excellent article which deals with pursuing an FLSA claim---which you may do in either state court or federal court. Do take the time to review it:
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I wish you the best in 2012,