Unfortunately, smoking weed does do this to certain people. I know someone in real life that is the same as you, can't smoke any weed because the brain goes all paranoid.
So, no, there is no real need to see a doctor.
As far as fixing it goes... well, can't say I know of a 100% sure fix but you could consider preparing more before smoking weed. So, making sure you've eaten properly. Just to negate anything on that front contributing to the situation. Also, make sure you're well hydrated before smoking. It might make a difference.
Finally and this is just a suggestion of which I have no idea how well it might work... try drinking small amounts of alcohol before smoking. Not enough to get you stone faced drunk but enough to get you buzzed a bit. It might induce a state in your brain that will negate the paranoia.
If all else fails, try smoking less pure. So, don't roll with just weed. Try rolling with tobacco instead. So, basically, mostly tobacco with a little bit of weed. Yes, smoking tobacco is bad, I know. But making the kick of the weed less intense might give your brain a bit of time to adapt.
You could then always just build up the ratio of weed vs tobacco, once you start noticing becoming less paranoid.
Last but not least... try and smoke in familiar surroundings. Paranoia is strongest when in situations or places that are the least familiar to us. So making to smoke in a location you normally feel 100% comfortable and secure in will also help.
I hope you found some useful suggestions and ideas here. Let us know how it worked out.
Good luck and... remember... enjoy yourself.
Edit: And no, it's not because of the OCD. That person I know in real life that cannot smoke weed either because the brain goes apeshit is without any OCD whatsoever. In fact, I'm quite OCD myself and I have no trouble with weed. Does not cause any paranoia for me.