My periods stopped around 1.5 years ago. They'd stopped (age 49), come back briefly (age 50 and a couple of months on 25ug of levo) then disappeared until June (age 51, 50ug of levo plus initial six doses of B12) and occurred again in July. GP has ordered TSH and LH to be tested. But, has anyone else experienced this? It's a bit disconcerting. Tx.