First thing to say is don't panic. There are several possible explanations for not detecting the LH surge.
LH surge may be too mild to be detected by the LH tests that you are using. May be worth trying a lower sensitivity LH test
Your urine sample amy have been too dilute. Make sure you restrict your fluid intake for about 2 hours before you take the test
You may have tested at the wrong time of day and missed the LH surge. Ideal time to test is early to mid afternoon.
The test strip may not have absorbed enough urine. Make sure that the control line is visible. This shows that sufficient urine has been absorbed, for the test to run. if the control line is not showing dip the strip into the urine sample again.
The LH test that you are using may be faulty. Make sure that you buy from a reputable supplier, and that the tests are in date and have been stored correctly.
You may be testing at the wrong time of your cycle. For women who have irregular periods, knowing when to test can be very difficult.
You may not have used the test correctly. Make sure that you read the instructions before starting the test and use a timer.
You may not be going to ovulate this month. This may just be a one off, but if it happens repeatedly you should see your doctor, as it may mean that you are not ovulating and need further investigations.
You may already be pregnant. There is always a small possibility that you may already be pregnant. If your last period was different to usual, or very light it may be worth doing a pregnancy test.