Can eating peanuts upset your stomach?

I have been eating peanuts almost every day for 2 months straight but I have noticed that:

1. I have gained so much weight

2. My stomach has been very upset, gassy, bloated, constipated.

3. I don’t get much acne

I wasn’t a fan of peanuts or related seeds because they made me get so much acne and at some point it was just enough... now I buy a perfect bar every day and peanuts and cashews. I have never in my life eaten peanuts on a daily basis but do you think this is causing me all those problems? The first days I did get horrible acne but I guess now my body is used to them.

I will make an experiment and STOP eating all of them for a week or so and see the results.