Do you have a career or did you do one of the hardest jobs on the planet as a SAHM? Do you have hobbies and interests that you have kept up with yourself? Do you and your husband have shared interests that you also take part in, together, just the two of you, or with other friends?
I ask all of these questions because this stage in life with teens and young adults, as they start to move away from time with parents, and navigate toward more or nearly exclusive time with peers, is difficult for hands-on parents.
How you cope is to re-discover a part of yourself that you put on hold when you began having children, or even before you got married or met your husband . . . OR . . . you "reinvent" yourself . . . OR . . . something in-between.
This could mean, if you do have a career outside of the home, taking on new projects or a new role, or returning to school for other skills, or a change in career.
This could mean taking a community class to refresh yourself with a lost hobby or skill to start again, or finding a new one.
Bring socialization with other parents in similar stages in life into the mix as well, and this gives you both a sounding board and safe space to talk about these issues and feelings.
If you do not have that in place, "make it." Start a book club and name it something along the lines of "Empty Nest Mums" or such, and ask for space in the community newsletter, or put an advert in the local market window.