Some other guy posted the same thing and I'll give u the same response I gave him. I have very similar thoughts and been dealing with them for about 7 months now and like you I have no reason to be depressed or suicidal and I know I'm not too I love my life, I just have these crazy obsessions. I'm afraid to do certain things like sitting in class, or going out with friends because I think to myself "what if I have these thoughts when I'm doing those activities" however it 95% of the time it doesn't stop me from doing what I want, I still go out with friends, go to the gym, school, work, etc. And I agree when I'm not distracted that's when I ruminate. I think about how these suicidal thoughts will eventually lead me to become hopeless and non functional and lead me to *****.
My psychologists has been saying for months for me to practice sitting (meditation) 15-20 minutes a day. And I just started 2 days ago as my new years resolution. The exercise is to literally just sit in a quiet room with your eyes open and do nothing. Just sit there and be aware of everything moment by moment. Whatever it is your focusing on whether its a feeling, a sound you just heard, visual things, a thought, emotion, feeling smell. Just be aware of these happenings and do not cling onto any of it. Just let it be there, don't control, or judge anything. Just observe whatever is happening non judgmentally.