CONGRATS!!!!
Yes, it's possible, men lose faster than women (difference in muscle and fat composition) besides, you've been through quite a lot right after surgery, your body has used up a lot of the extra that you've been carrying around for years and years, so you're set to lose in that respect, too.
So long as you are keeping up with your protein, water, and vitamins, you're fine.
Your dizziness may be from lack of something or from orthostatic hypotention due to the fact that your body hasn't yet adjusted in that respect, to the weight loss.
With sleeve gastrectomy, malabsorption is less of an issue compared to bypass, so, if your intake is in good balance, they the rest should be fine.
(((((HUGS))))) Way to go, keep up the good work!!!