Khabarji,

I was in the same position last year. Let me explain what I did and what you can do too.

What you can do is wait until the first week of June to apply for your tax return to qualify yourself as a resident by the substential presence test. However, you have to file form 4868(Application for Automatic Extension of Time To File U.S. Individual Income Tax Return)

and pay the applicable tax with your 4868 form as if you are filing as 1040NREZ. You have to calculate the tax as you would pay had you have to file 1040NREZ. They will not even ask you how did you calculate this figure. Just calculate this figure the way you use to do before while you filed 1040NREZ. You will get your money back after you file your tax return (1040) in the first week of June after.

After the first week of June, you will meet the substential presence test to file the tax return  as a resident and at that time you can use form 1040. For further details, you can read publication 519 available in irs.gov website.

Hope this helps and does not create more questions for you!