I’m confused

I recently lost my great grandma less than 4 months ago and we were extremely close. She was very sick and I knew it was her time, it just hit me really fucking hard. I’ve noticed every since then I just get random waves of sadness. I’ll go out with my friends and I feel happy in those moments. I’m not always sad at home and I don’t always lose my appetite but I just have moments were at night I can’t help but to bawl my eyes out. Then this week I found out my grandma (my great grandma’s daughter) cancer might’ve come back bad this time. Today I found out it might’ve spread to her whole body, and I was fine for a couple hours but now I’m crying uncontrollably. I just feel so scared and angry this is happening to her. She’s spent the last like 6 years taking care of my great grandma and this is her first time being alone and this happened. We won’t know a 100% for sure until Monday because of the test results but her doctors are saying it doesn’t look good. This news made me spiral even more. I’m at the point now, where Idk if I’m falling into a depression, if I’m still grieving and this news is just hitting me harder and I should seek help or if I’m just being over dramatic. I’ve only told my best friend because I don’t want to tell my family and they think I’m just being a drama queen but I’m kind of concerned. I haven’t felt this sad and had these literal meltdowns where I just sob in a longggg time. I don’t know what I should do.