アラシと間抜け混同すんな。

外で曇ってて、だるい感じがするー

Took Elenkis’s answer since its all correct.

Hopefully the non Danish Mark sees this.

1. 以来 means since. With verbs it attaches to the -て form.

2. “しなきゃいけない” means “must do/have to do” and it’s a contraction of “しなければいけない”. In casual speak the いけない often gets dropped, leaving just “しなきゃ”. There are several similar ways to say “must do”, such as “しなくちゃいけない/ならない” and “しないとだめ”.

Here is all the possible combinations that you can do to say “have to”
Negative te-form + 「は」 (wa) particle + だめ／いけない／ならない
Negative verb + 「と」 conditional + だめ／いけない／ならない
Negative verb + 「ば」 conditional + だめ／いけない／ならない

http://www.guidetojapanese.org/haveto.html#part4

You can basically read all about it here but one thing that I want to stress that is also mentioned in the link is that:

On a final note, in general, 「ちゃ」 sounds a bit cutesy or girly. You’ve already seen an example of this with the 「ちゃん」 suffix. Similarly, 「なくちゃ」 also sounds a bit cutesy or childish.

Other thing is that when you want to make a relative sentence using “have to do”, you must add the end to it (いけない、だめ（な）、ならない）

3. “わけじゃない” means “it’s not the case that—”, “it doesn’t mean that—” etc.
“しなきゃいけない理由があったわけじゃない” = “I don’t mean that there was a reason I had to do it.”
Present tense would be “あるわけじゃない”.

4. “わけない” is shortened from “わけがない” and it means “there is no way that—”, “there’s no reason why—” etc. In other words the speaker sees it as impossible.

ということで、並んで比較すると

わけが ない 　→　 There is no reason
わけ じゃない 　→ It does(is) not mean that

5. “-てよかった” means “I’m glad that–” or “It’s good that–”.
俺はこれを読んでよかった。

Literally, “I did this, and it was good”. When you translate that into the situation instead of being directly translated, it means something to the extent of ““I’m glad that–” or “It’s good that–”.”

The second half doesn’t sound like me at all :/

Then hit me up through my email ( missingno15@gmail.com ) unless you’re completely ok with posting your skype username here then its all good