I forget sometimes instantly ? can omegas or multivitamins or memory booster help ?

Can't guarantee: I'm sorry, but without a workup to provide some idea of why you're having memory problems, i can't guarantee supplements would help. If you're eating a poor diet, multivitamins and omega 3's are certainly worth at least 6 months' trial -- but you need to also see a physician for a thorough assessment. Be well.

Stress level high?: Instant forgetting sounds like it never even had a chance to register and settle in. Perhaps there's an attention/consciousness issue keeping a memory from forming. Try relaxation breathing (full exhale. Nice deep inhale. Comfortable hold. Full exhale - several times) now, test a simple memory & see if it's better. Stress can really mess things up. Then you can consider supplements. Best!