I having all the symptoms of a menstrual period but I'm not bleeding. Can the blood just get re-absorbed by uterus?

Minimal endometrium. Sometimes, the lining of the uterus(endometrium) doesn't grow very much in response to hormonal stimulation and therefore, the menses(blood flow) is minimal. This event is also common when the oral contraceptive pill is used as it is designed to keep the endometrium "short" , thus 2 or 3 days of bleeding.
No. It is more likely the lining of the uterus has become very thinned so there is no blood or lining to be shed when the hormones give the "period signal". This is why women sometimes have typical symptoms but no periods after an endometrial ablation, Mirena (levonorgestrel) iud, oral contraceptives, or during perimenopause.