Upvote:2
I'm afraid I would be turned down and could never return to the UK
Any time someone pronounces that phrase in relation to UK immigration, a magical piece of advice inevitably pops up here on Travel.SE:
Apply for an entry clearance/Standard Visitor Visa
Making an application for a UK visa is not particularly difficult in your circumstances as you're a non-visa national who is resident in an EU country and who was formerly a UK resident. It will cost you 90 pounds to apply and a trip to the UK consulate, but it will be worth the effort. Once you arrive at the UK border with a previously issued entry clearance, the immigration procedures will be mostly a formality as the Immigration Officer will be a lot more confident that he's dealing with a genuine visitor rather than someone trying to build up a life in the UK without going through the appropriate channels.
Note that the duration of your visits would still have to be sensible in regards to your status as a student, but going every second weekend is definitely more than reasonable.