The chances of 5 pregnancy tests all being wrong are very, very small. However, there is always a chance you could have made some unnoticed mistake in doing the test, and it's not good for you to be worrying like this, so it may be advisable to get your doctor to have a look at you, and perhaps ask him/ her to do another test.
5 months is a long time ago but when you've had a miscarriage it can take a while for the levels to drop go c your doctor because it could be just the levels frm be4 your miscarriage gd luck !X
If your test results are positive then there is nothing wrong with you. You must be hopeful now and you must also be in touch with the doctor for check ups, tests, ultrasound, special precautions and medicine.