grief & loss

hi carer community, i am new to this forum. i have two adult children whom i care for, a 30 year old son who suffers from schizophrenia, and a 28 year old daughter who lives with bipolar disorder. my daughter was diagnosed at 16 years of age and my son at 19 years. over the years i continue to struggle with a sense of loss and grief. a sense of loss for the turn their lives have taken and limitations that i can see the illness has imposed. grief because i see their suffering year after year as they each try to work through the hurdles life has thrown. sometimes i think i have reached a level of acceptance and then somewhere (seemingly out of nowhere) i feel overcome with these heavy sad feelings tinged with a large dose of fear. so it is as if we are all on some type of roller coaster and its scary.