it's up to you. i recently lost both my purple veiltail, Purple, and my blind white HMPK, Theodore. after losing Purple, i'd been prepared for his death, and i felt i was ready to get another one after losing him. however, after losing Theo.... since his death was so sudden, i felt like i didn't want to get another. HOWEVER.... after finding a beautiful baby blue boy on Ebay, i find myself wanting him badly, but the amount he costs keeps me away(he's over $30 total! no way i'm paying that much for a betta!)...
then, there was my brother, who had his CT, George, and his dragon HM, Archfiend. he felt that 2 was more than enough for him, and didn't want another. well, Archie got popeye, and we were treating him for it. we were at the pet store one day, and he found a boy who called for him, a little pink, blue, and red boy, real odd colors. he NEVER had that happen, so it was really odd. he got little Wheatly home, and that's when we found out... Archie had passed. it was like Archie was telling my brother goodbye, thanks for caring for me when no one else would(he'd been there long enough to tail bite and get fin rot really nasty...), thanks for being a good daddy.... it was really touching, ya know?
so... it's up to you, if you want a new boy or girl. give yourself a few days. if you can't handle seeing his tank empty, then get a new one. :d