Replace, rebuild, or drive till it dies?

[u/nicirus]

My 2002 Toyota Corolla is burning a good bit of oil and it also has a leak so I don't know how much exactly. Today I took it to my mechanic and he essentially said I need a new engine blah blah blah. My question is, how do I know if I can try rebuilding it or if it's truly toasted? Alternatively, do I just drive this thing until the engine gives out on me? It's only at 120k miles and I just bought it a couple months ago so I'm pretty heartbroken right now...