On attempting reentry with tourist pass after being rejected

I was rejected from entering Singapore today. I need some advice on how to re-enter.

I was in Singapore for about 80 days on a tourist pass and then went to Johor Bahru in Malaysia for about 5 days. I wanted to come back to Singapore for under 90 days and wrote down on my immigration card 90 days. While at immigration at Woodlands, I was brought in for questioning about what I was doing in Singapore, the cash I had, credit cards, etc... I told them I was intending to stay in SG again to relax on a gap year and career break and wanted to stay longer to consider moving there. Unfortunately, they told me that I couldn't enter Singapore and I had to go back to Johor Bahru. They gave me no specific reason why and would not divulge.

I would like to come back to Singapore soon and stay for a 2-3 months only once more before I head back to the USA (and possibly have applied to companies here). I heard lots of people do this for about 3-5 times so a bit surprised since this is my first re-entry attempt, but I am aware that this is all at the discretion of the immigration officer.

Did I just get unlucky? Is it possible for me to return soon? Anything else I should try?