To forget old bad times like depression.

Is there any therapy or treatment to make me forget about unwanted things happend in my life? Because last 4 yrs of my life was very bad with negative thoughts ,doubting my fiance,my parents,and i lead through most diificult part in my life but Alhamdulillah I recovered a lot from that but at times it will come to my mind and i will start rethinking about it and i will get into that mood for somedays . Sleepless nights,anxiety all were there and lot of negativ vibe of i see anything i will b able to collect negative from that only . I don't want to live like this because peaople whom all are surrounded by me are feeling for this. Mostly my fiance ,so is there any treatment ,therapy or through hypnotism will i b able to forget all this thing?