i have the exact same problem, my moods can change from being very happy so very upset and depressed in a matter on minutes and can happen several times a day, and it can get really annoying, there is a type of depression that specifically relates to the mood swings that change very very quickly, it very hard to control these mood swings but remember mood swings are apart of depression and depression is an illness just the same as asthma etc. but you can't just gain control instantly, it has to happen over time, and with the right help and/or medication you can gain control, but it will take some time
im here if you ever need to talk
take care
vikki x :hug: