beautiful dream but made me feel miserably lonely

Hi, im new here ad i wanted to know if someone could help me interpret my dream, cause it was very nice but it made me miserably lonely to the point that i woke up with tears. I currently life abroad wich explains a bit about my dream.

I dreamt that i was back home, but apparently a couple of years had passed without me noticing, so i meet my 23 year old sister who tells me shes getting married now, she looks radiant, and tells me shes been engaged for over a year, which i dont remember, and that shes pregnant and shows me the ecography, and i am so happy i cry of joy. than she tells me my little brother and sister are great (my dads kids) and that my mother´s baby is so big now (my mother does not have a baby), and i dont remember that i have this new little brother called "Sergio" who is 2 years old, and when i see him he looks exactly like my mother as a child, and i cant stop hugging and kissing and playing with him, also crying of happiness, but also of guilt, because i didnt even remember him, and i saw everyone living these beutiful lifes with their own families and i am so happy for them but at the same time i feel so lonely and sad and guilty for being away.
I miss my family but i dont feel guilty for living abroad and dont feel specially alone.
please help me decipher my dream, i woke up crying and with all these mixed feelings...