A female question?

I'm 51 years old and thinking i'm going though the change of life.Shorter periods in between periods my cycle is changing from 28 days to 24 days now 21 days it seems like i'm PMS'S all the time i feel cranky and moody and sleepy and can't and i mean can't stop eating sweet and salty stuff,My question to anyone out there that has the same problem please let me know if its menapause or what?I just finish my period 2 days ago and now its starting up again my are starting to get sore again and i have aches all over just not myself anymore,i use to be a active person now i don't want to do anything anymore,its starting to effect my marriage and our way of life..What can i do to feel better and if it is menopause how long does it last until i have no more periods,then what how does one feel when the periods stop,are your moods worst or do you feel better what???Please help Thank You for any info..