Best relationship I've been with in awhile and feeling confused.

Lately I have been feeling sad and confused about my current relationship and where it is going. We've been dating for the past 7 months. He's everything I ever wanted from a partner. A hard worker honest,faithful,there for me when I need him (if not in person than a phone call away we are long distance) good to his word, he's a family man, loving, always is there and looks out for me. Will do just about anything to please me and make me happy etc. Which I do the same for him. While he isn't perfect nor am I. For some reason I haven't felt the same about us or happy. Nothing ever happened we haven't fought or anything. I take medicine for anxiety and depression (possibly my meds are off) and lately I've just been sad and emotional. Idk if it has to be with my relationship or not. I have also been snapping at him almost picking fights. Which just isn't like me. With everything there's been some some sick family members which has been very stressful he's been there. That also could be the reason I haven't been as happy or go lucky. Just wish I didn't have this sad feeling of just doubtfulness and worry I'll lose him or something will change. Ill decide ro walk away and regret it. I know he wpuld make a wonderful dad and husband. I'm scared and freaking out and idk why.