No need to be nervous, this is anonymous so all good.
Throughout your post you do display anxiety and intrusive thoughts that you have little control over, this is common and curable. Your first step, that of knowing you have a problem has been taken and well done there, many people dont recognise it. This is called insight and it is a welcome gift you have. That alone will help you get through this.
A long time ago I had such a condition and had to seek therapy for it. During those sessions for 10 months, I had to be reprogrammed so to speak, by learning when to ask myself "are my thoughts being realistic". Each time I did this I had to discount thoughts that was made up of imagination and fear. To be blunt- I was my own worse enemy because many of the things that were created in my mind were not real but I reacted to them. This accelerated my anxiety for some time.
Eg you seemed to enjoy your attention with your boyfriend that day, if he has felt you were making him uncomfortable he likely would have told you there and then. When you asked him later he denied feeling so, therefore you should have taken his word for that reply as you then confirmed your thoughts were "real". Instead you are creating turmoil and upset, effectively allowing possibilities to overshadow a perfectly good relationship.
For this reason you could well do with a GP doctors visit and tell him/her what is going on. Sometimes we need help at various stages of our lives to get over the hurdles and prevent issues growing out of proportion. I did and have never regretted it. Such conditions can place extra unwelcome pressure to a relationship and can ruin it. Therapy can get to the heart of the problem like being insecure for a reason which could date back to earlier in you life. Otherwise the problem never goes away it just becomes idle for a while then comes around again during other lifes events.
I hope I've helped
Beyondblue topic worry worry worry