jag och min far

As you already know, “far” is “father” and “mor” is “mother”.
If you look to your dad’s side of the family, you would call his father “farfar” (“father-father”) and his mother “farmor” (“father-mother”).
The same method goes for your mom. Use “mor” at the beginning and follow it by another “mor” or “far”.

En - Sv
Grandfather on the father’s side (father’s father) - Farfar
Grandmother on the father’s side (father’s mother) - Farmor
Grandfather on the mother’s side (mother’s father) - Morfar
Grandmother on the mother’s side (mother’s mother) - Mormor

Remember as combination words, these take on the forms of the last part of the word.
en mormor - mormodern - mormödrar - mormödrarna

You can also talk about your father’s or mother’s parents together as a collective. It’s done the same way, by adding “parents” to the end of “father” or “mother”.
Grandparents on the father’s side (father’s parents) - Farföräldrar
Grandparents on the mother’s side (mother’s parents) - Morföräldrar
Again, remember the forms. If you want to talk about a single grandparent on the father’s or mothers side without specifying whether it’s a grandmother or grandfather, you would use the singular forms (ex. morförälder - morföräldern).
If you want to talk about all of your grandparents as a collective without saying “mina farförälder och morförälder” (my father’s parents and my mother’s parents), you could say “mina föräldrars föräldrar” (my parents’ parents).

You could keep building up to create great grandparents, great great grandparents, and so on.
Mother’s mother’s father (great grandfather) - Mormors far
Mother’s mother’s mother’s mother’s mother - Mormors mormors mor
Father’s mother’s mother’s father’s father - Farmors morfars far
I have also seen people say “gammelmorfar”, “gammelmormor”, “gammelfarfar”, or “gammelfarmor” as terms for great grandfathers or great grandmothers on your mom’s or dad’s side.

This same method of sticking two words together can apply to grandchildren.
Daughter’s son - Dotterson
Daughter’s daughter - Dotterdotter
Son’s son - Sonson
Son’s daughter - Sondotter

If you don’t want to specify, “grandchild” would be “barnbarn” (“child-child”)
“Great grandchild” would be “barnbarnsbarn” (“grandchild’s-child”).
Grandchild - Barnbarn
Great grandchild (grandchild’s child) - Barnbarnsbarn
Great great grandchild (granchild’s grandchild) - Barnbarns barnbarn
Great great great grandchild (grandchild’s grandchild’s child) - Barnbarns barnbarnsbarn
Great great great great grandchild (grandchild’s grandchild’s grandchild) - Barnbarns barnbarns barnbarn

“Aunt” is a mix of “mor” or “far” and “syster”.
Aunt on the mother’s side (mother’s sister) - Moster
Aunt on the father’s side (father’s sister) - Faster
“Uncle” is a more straightforward mix.
Uncle on the mother’s side (mother’s brother) - Morbror
Uncle on the father’s side (father’s brother) - Farbror

“Cousin” (your aunt or uncle’s child) in Swedish is called “kusin”.
en kusin - kusinen - kusiner - kusinerna

En: I have three cousins on my mom’s side and two cousins on my dad’s side.
Sv: Jag har tre kusiner på min mors sida och två kusiner på min fars sida.
En: Our grandmother always bakes cookies when we come to visit.
Sv: Vår mormor bakar alltid kakor när vi hälsa på.
En: Her grandchildren are very creative. The daughter’s son is an artist and the daughter’s daughter is a musician.
Sv: Hennes barnbarn är jätte kreativa. Dottersonen är en konstnär och dotterdottern är en musiker.
En: My uncle’s house always smells like cheese.
Sv: Min morbrors hus luktar alltid som ost.

När jag var liten och skulle åka utomlands för första gången sa min far “Bäst att inte drömma om det så jävla mycket då blir du bara besviken när det inte blir av”. Så känner jag nu. Jag vill så gärna att det här ska bli bra, men vågar inte ens hoppas för det gör så jävla ont när man blir besviken sen.