Hello Lulex: I see this is your first post here on PC. So... welcome to PsychCentral! I hope you find the time you spend here to be of benefit.

I'm certainly no expert with regard to the sorts of things you're experiencing. But my thinking would be that what you're experiencing are perhaps bouts of paranoid-type thinking caused by temporary spikes in your level of anxiety... some related to sexual activity... others related to other sorts of things such as your grandfather dying.

Perhaps you are kind-of an anxious person anyway? But then, when you are in a situation that is anxiety-provoking for you, you have these spikes of anxiety & they in turn cause you to have temporary paranoid thoughts. At least this is my non-professional take (for what it's worth) on what you describe.

Here's a link to an "Ask the Therapist" column, from PsychCentral's archives, where a young person wrote expressing concern over experiencing mild paranoia. I've included it because I liked the reply the therapist wrote:

https://psychcentral.com/ask-the-the...ld-paranoia-2/

Also, on the assumption that what you are experiencing is perhaps related to anxiety, here are links to some articles on the subject of how to deal with it:

https://psychcentral.com/blog/3-prac...-anxious-mind/

https://psychcentral.com/lib/9-ways-...ere-right-now/

https://psychcentral.com/lib/top-10-...s-for-anxiety/

https://psychcentral.com/blog/11-tip...anage-anxiety/

https://psychcentral.com/lib/15-smal...iety-symptoms/

I don't know, of course, if you're here simply seeking advice with regard to this particular concern or if you plan to continue posting. However, should you be planning to continue on (we hope you do)... may I suggest you introduce yourself over on PC's New Member Introductions forum? Here's a link:

https://forums.psychcentral.com/new-...introductions/

There's a lot of support that can be available here on PC. The more you post, & reply to other members' posts, the more a part of the community you will become. Plus there are the chat rooms where you'll be able to interact with other PC members in real time (once your first 5 posts have been reviewed & approved.) So please keep posting!