Various verb tenses

Question

Hello, i'm probably getting ahead of myself (only been studying French for 2 months) but wanted to see if anyone would be willing to let me know if I'm correct or not on below conjugations.
I ate = j'ai mangé
I was eating / used to eat = je mangaisI should eat = je devrais mangerI will eat = je mangeraiI should not eat = je ne devrais pas mangerI will have eaten = j'aurai mangéI will not have eaten yet = je n'aurai pas mangé encoreI had eaten = j'avais mangéI had not eaten yet = je n'avais mangé encoreI have to eat = je doit mangerI can't eat right now = je ne peux pas manger maintenant/tout de suite?I should have eaten = j'aurais pas dû mangerIt seems in general that "should" future uses conditional present and "should" future uses conditional past.I apologize in advance if this is too much for a single post :(

Accepted Answer

I had not eaten yet -- Je n'avais pas encore mangéI have to eat -- Je dois mangerI should have eaten -- J'aurais dû manger

Answer

oops, correction.
I should have eaten = J'aurai dû mangé ?

Answer

Merci beaucoup!  I realized I had a couple stupid errors in my original post (je doit, par exemple eek) & the "pas" in my translation of I should have eaten - oops! 
I understand my error in reposting "Je aurai dû..." should have been "aurais", (because doubt, certainty, wish, etc. requires conditional?) i think that was a typo the 2nd time around.  I guess i had that correct initially (minus the "pas"), and shouldn't have changed the verb form for manger.

I need to read up more on the placement of adverbs such as "encore" around the pas, that is a little confusing to me.  To me, the "encore" sounds better after pas, but that obviously doesn't mean anything.

Oh also to say "right now" in that context is it better to say maintenant or tout de suite?

Thanks so much!  This site is awesome, i'm learning a lot from it.

Answer

oh and i had a spelling error.  I used to eat s/b Je mangeais.
thanks again.

Answer

For "right now", either maintenant or tout de suite is fine.  For my feeling, tout de suite carries a bit more urgency, but I might be wrong.