Mood swings

I was feeling sad for about 2 months but then these last 2 days I was EXTREMELY happy but then I became sad again…This always happens to me, First I’m sad for a LONG time (like a month or 2) and then I’m happy for like 4 days or maybe a week then I become sad again. Every time I become really happy something bad happens and I become sad again.Yesterday was worst I went from sad to happy to mad and all over again Whenever I’m happy my mood is unstable and I even laugh at things that don’t even make any sense, but when I’m sad nothing matters and I feel alone or I start feeling mad because no one cares about me.Today I’m not as sad as I usually am so I’m just going to relax and listen to some music…