Frequent

The lows happen more often.

Why do you think is it?

Corrected:is it so

Are you male? This is a man's opinion.
If you have ever fallen in (and out) of love, the feeling might be familiar.

Yes.
That is because when you love someone, you become addict to her.
Jokingly, I'd say:
Get used to loneliness, dear, for catastrophe arise from women
fortunate is he who avoids women

the original poet (from the Persian poem,Hafez(PBUH)) has 'individuals' in place of women

Lows = feelings of despair, loneliness, sadness, sorrow, misery
Highs = feelings of elation, love, happiness

Does 'highs' just mean being in high spirits? Hafez (PBUH) also says
'Yes, by virtue of your good graces, clay turns into gold

I'd use them about women. I got milder after I became a lover. I learned patience from a woman in our class, and many things.

They also are more strict, lie more often, etc, and that makes you sad at times. I have become distressed during this semester and I decided to either abandon my university, or do something else.

soheil1They also are more strict, lie more often, etc,

There are many women, and quite a few men, who would consider that statement somewhat offensive.

The solution is to be more lenient, be more frank, etc.
I judge by many women I saw. I shouldn't have generalized, you are right.