Whatever your opinion on sovereignty, immigration and the rest, I have seen absolutely no convincing arguments that the Brexit will do anything other than seriously harm us economically in the short to medium term. If we were to leave and prosper then it would evidently create a domino effect whereby all the other EU countries look to leave. For this reason the EU as an organisation can absolutely not afford us to do well out of a leave vote. If we do leave we will suffer, and that isn't "scaremongering" it is basic common sense.
Not trading with us would hit the rest of the EU very hard, which makes it unlikely to happen, plus some of the key players from the EU have said that there is no chance that they'll restrict trade. Most of the "predictions" of doom haven't stood up to scrutiny.
The same was predicted for Norway during their two referendums, and was found to be very wrong there after the vote.