<human>: Can you summarize the given text in a few sentences?

I have had some depression but my life was so cool I would play tennis and work out 3-4 times a week. Would be so happy going out with friends. I would have low days too but I had happy days as well. I never went to a therapist or took any anti-depressants.

I met this amazing girl 7 months ago. She is lovely, everything I could have asked for. 3 months ago, I got suspicious about her best guy friend. I was straightforward and asked her about him if there was anything between them. She told me there was never anything but they are very good/close friends. And also that guy is not her type anyways. I had a gut feeling like I had in the past.. that something was not right. I asked her. She clarified. I trust her. 

But I have not able to get this feeling out. My ex gf had a guy friend too. I never felt this way. My stomach just keeps churning. And these imagined things keep coming to my mind. I am going to therapy. I am trying to be more mindful. Therapists are asking me to take anti-depressants. 

I am not sure if I should go with anti-depressants (SSRIs). I love her and she is so amazing. But these thoughts just haunt me. They keep playing in my head. I am in vegas with my friends and I am writing this post. My stomach is churning. My chest is heavy all the time. I have not been able to sleep well for weeks. My mind is just crazy. I have not been happy in the last 3 months except when I am with her. 

I am 100% sure there is nothing between them but my mind keeps playing stuff from the last 3 months. How do i stop it?

Someone, please help me. How to fix my mind? Is it really depression. My heart says no. It is something else. Please help me. I am tired of staying awake, tired of being sick, tired of not being happy, tired of this thought in my head, tired of crying.  I am tired
<bot>: Girlfriend has a best friend. She says nothing. I trust her.  But the thought is not leaving my mind. Doctors say depression.