I was wondering is 45 points is just the maximum a person can have at any given time or if that also means that one can only earn 45 points each day. I am trying to get out of the negative and I'm just wondering how long that would take me.

You can request a points reset to zero in the frihost support forums.

There is a limit to the number of points you can earn in a day, but it's limited by the time available in the day to create 5 point posts... functionally, it's not limited.

Points earned BEYOND (positive) 45 points are converted to coins at the end of the day, resulting in a max of 45 available at the end of the day.

This post, for example will likely earn me about 3 points, after which I'll have 47 points. A few hours later, I'll be dropped back to 45 and the remainder will earn me coins.

In your case, if you earned 200 points today, you'd be at -18 points....

If you earned another 78 points tomorrow, you'd reach +50 points; at the end of the day you'd be reduced to 45 points and you'd earn some coins.