I pronounce ich like "eesh". is this terrible? I have a friend who's doing a Ph.D. in German and she told me this is wrong. But on Duolingo this is what I feel like the voice is saying during the lessons. Is it okay to pronounce it like this or not?
There are regions in Germany that pronounce this "ch" as "sh". It's not the standart pronunciation but you would be understood. However, if you want to do it "correctly" and have problems with pronouncing "ch", try smiling when saying "sh", that moves your lower lip away from your teeth, and the "sh" should turn into a "ch" :)
You definitely need a short "i" in the start of the word. Like in "kid" or "it". If that is done all versions such as: "ick", "ish" or however you try to come close to the "ch" sound will be understood. Some are also regional dialects others are just display of your accent.
I hope I could be of help.