My periods are always regular. Lmp was feb27th. All hpt show negative but have had all symptoms. Now I'm bleeding heavily and cramping. Is this miscarriage?

If you have had negative pregnancy tests, it is more likely that your cycles were off and this one is sort of making up for what you have missed. It can happen where a cycle will be skipped, for no apparent reason and that may be what happened.

It is possible that you just didn't get a positive result on your tests and this is a miscarriage, but usually you would have had other symptoms as well.

See what happens over the next few days. If this continues for about the length of time a regular period would for you, it is likely what it is. If you find that you have extended bleeding, you could always contact your doctor and have it checked.