I had gynecomastia, but thankfully had surgery (private) to deal with it two years ago, it got my life back on track. I cannot push you enough to get this surgery.
Before my private surgery, I did get an op on the NHS, but they only did liposuction, the surgeon didn't want to do any excisions because I was only 17 at the time. This did not cure the condition at all. Gynecomastia is caused by glandular tissue on the breast, only a combination of removing this tissue and lipo will deal with the condition.
Private surgery (there's some great surgeons in the UK, strongly recommend Karidis in London), can get your chest right, they are expensive, but totally worth it.
My advice is to work, work, work, save up the money. Maybe get relatives to chip in.
Importantly, DON'T get depressed. Think about it, there's actually a way to cure this problem, many others with far more serious conditions don't have that luxury. End of the day, you can get this op done, even if it takes some time to save up. Concentrate on that instead of wasting time feeling down. That won't solve your problem.