"I have an extremely good academic record but I can't say I blame companies for not taking that too seriously."Nonsense. Despite the conventional wisdom on HN, most companies highly value students with good grades. We just also want people who can code. If you can do both, you'll be fine. But...it takes a while to land the first gig. That's totally normal, and has very little to do with the status of your github account. Do not believe people who tell you otherwise, because they have serious problems with perspective.
The fact is, if you've just started hunting, you're looking for work late in the recruiting cycle. Most larger companies recruit at the beginning of the school year (autumn), with a smaller effort sometime after the holidays. So if you're starting now, you're going against the tide, and it will be tougher to get attention.
If you can code, and your grades are as good as you say they are, send me your resume (my HN user at yelp.com), and I'll put your application in at Yelp. We're always hiring smart people.