Lots of people struggle with it.
Here is RWA's (Romance Writers of America) baseline definition of romance:
Two basic elements comprise every romance novel: a central love story and an emotionally satisfying and optimistic ending.
A Central Love Story: The main plot centers around individuals falling in love and struggling to make the relationship work. A writer can include as many subplots as he/she wants as long as the love story is the main focus of the novel.
An Emotionally Satisfying and Optimistic Ending: In a romance, the lovers who risk and struggle for each other and their relationship are rewarded with emotional justice and unconditional love.
Beyond that, the variables are endless. Without both, you don't have a romance. So that's a check-markable thing. If you meet the criteria, great, if not, then you have to drill harder. From what you've said, you're right, it's not romance.
So, there's Women's Fiction, which is generally oriented around a FMC's emotional journey, often with an important cast of love interest(s) and/or family and/or friends.
Past that, as Tazlima indicates, we'd have to know WAY more about what you have on your hands. It could be mystery, it could be mainstream, it could be thriller. For querying purposes, often stories combine/cross genres so nailing down one can feel stressful. You just have to try to pick the most representative. Nothing is written in stone. It's only so you can target the right agents and help them envision your book on the shelves. If you're SPing, you have a lot more latitude.
Is the book written? If not, unless you're hoping to get in on some category thing with really strict guidelines on how they're written, I wouldn't sweat it too much.