Am I just paranoid???

It takes 2-3 days for semen to even inseminate the egg. You would physically not have any symptoms whatsoever even if you had magically become pregnant the moment you coupled. You are simply letting your nerves wrack you into imagining symptoms.

Relax.

There is no way that your mind can convince your body that you are pregnant, and actually cause a pregnancy out of that. The only way to become pregnant is if your precautions have failed. Try to relax, and calm yourself down. Remind yourself that you took many precautions and you will be fine. If it stresses you out too much you can buy a pregnancy test. Either buy one yourself, get a parent, or a friend to get you one. Or even your boyfriend. Or, you could wait it out a bit, for your period to come. Once your period comes, you will for sure know that you are definitely not pregnant. Or, you could see a doctor and they will give you a pregnancy test. This is your first time, and it's normal to feel paranoid about this. But the chances of you being pregnant is basically none at all. Don't worry.

I had something like this and from what you are showing, its VERY unlikely you are pregnant, keep calm, have some tea or a hot drink you like and relax. like luminescent said, thinking that you are pregnant will not give you symptoms of being pregnant, however the stress of it you are making can affect your period, I panicked and I skipped a month from the stress of the thought, which can make matters worse over thinking wise, plus its only been 3 days, even then your unlikely to suddenly become pregnant and show signs of it in just 3 days. if it really worries you wait out for a week or two and buy a pregnancy test :)

If you keep feeling paranoid like this then just don't do it again, so the feeling of paranoia doesn't come back. I find it highly unlikely because you took all the precautions and as you said he did not ejaculate so you should be good. Just try not to think about it and distract yourself by relaxing or listening to music or watching funny movies.