All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
Hajj is obligatory once in a lifetime on every Muslim after he/she reaches the age of puberty provided he is capable financially and physically and did not perform Hajj before (after he became pubescent); whether he/she had performed ‘Umrah once or 1000 times, or never performed ‘Umrah at all. Saying that whoever performs ‘Umrah once must perform Hajj is not correct. There is no connection between the obligation of Hajj and the performance of ‘Umrah. Further, it is permissible to perform ‘Umrah before performing Hajj.
Therefore, since you are unable to perform Hajj, then you are not obliged to do so. For more benefit, please refer to Fataawa 82165 and 82631.