All of these things can help.
Most week days, you can/should say Psalm 137, (as opposed to Psalm 126), before Grace After Meals. Many booklets that contain Grace After Maals have this in them already. It is a very sad lament and it certainly gives one pause if one take a few seconds to contemplate the words.
Baal Halachot Gedolot brings down a series of fasts, one of which is on every Monday and Thursday, for the destruction, (see the last few lines on the third page). Bear in mind why you are fasting.
When you are overcome with laughter, remember the verse in Psalm 126 that says "then the laughter of our mouths will be filled". Realize that the notion of carefree, full on laughter without the Temple is strange, and discouraged, (see here, I believe this is based on the Talmud in Brachot, 31a)
Find two small pebbles. Put them in your socks. they should not be so large or jagged as to be painful, just something that you notice as you walk. One for the First Temple, one for the Second.
You can purchase scratchy burlap fabric very cheaply at any fabric store, and make a tunic to wear under your clothing. It is very irritating at first, but once you get used to it, it is another reminder.
Learn how to sing Lamentations with Cantillation. Wake your self up in the middle of the night, sit on the ground uncomfortably in the dark with a small candle, and sing a chapter of it, trying to think of How Jeremiah must have felt writing it.
Learn Laws of Sacrifices and Temple service. A good start is found in most prayer books. It is a section right after morning blessings, titled "Korbanot, Sacrifices". Realize that what you can only learn about was something we were once able to actively do. Think about how you would feel if you suddenly could only hear descriptions of the commandments of Matza, or the Four species, or Sabbath and could no longer active perform them! Realize that the only reason you don't 'get it', as far as sacrifices and Temple service goes, is because you never knew from them when they were a physical reality, and neither did your parents, or your great-great-grandparents. Realize how long it's been. Realize how sad that is! ):
Take a few minutes aday to think of human trafficking, institutionalized sex slavery. Think of all the young girls who are treated like things and abused casually by animals of men. If human trafficking doesn't make you exceptionally sick, try to find a pervading problem that does. Realize that, even with the amount of money and man power that is exerted world wide, these travesties endure. Realize that the Messiah will end these things forever. Realize that he can come today! ... if you obey God's will, (Sanhedrin 98a). Realize that we can bring the Messiah any day. We can stop these atrocities any day. It depends on us! By extension, everyday we fail to bring the Messiah, we perpetuate these terrible crimes.
Hope some of these are found to be useful. The fact that one recognizes that one doesn't care, and that it bothers one is commendable.