Viviprudolf, ms affects people differently so there's no way to tell what symptoms someone might have, when.
One person may have their speech affected but still be able to think coherently without being able to put their thoughts into words comprehensibly; another person may suffer disordered thoughts or confused thoughts while being perfectly able to speak. If I get tired, for instance, my speech deteriorates.
Motor functions are often affected, so you might be able to think effectively or plan to walk to the shops to get milk, but not actually be able to do it as you have little or no control over your legs, or when you get to the shop, you can't remember why you are there.
Anything that uses your nervous system can be subject to attack at any time, which means that there is no certainty at all about what you may or may not be able to do now, in 5 minutes' time, tomorrow, next week and so on. Attack can be as simple as an increase in pain and as massive as losing one whole side of your body (happened to me when dd was about 2yo; it came back after a few months though). Sometimes I discover that a tiny bit of my the,b, for instance, has gone numb. Days or weeks later it's back! Sometimes I can write neatly in my normal hand writing, sometimes my writing is the illegible scrawl of a 3 yo.
I have completely lost my legs for instance, but luckily they came back - took about 3 years altogether, but I can walk though not far and not without pain. In fact, pain is also a constant companion, sometimes it's not too bad and sometimes I can barely move because of it and so spend days in bed.
MS is usually accompanied by fatigue. This is not like you might feel after a busy day at work, this is utter exhaustion from just being awake! Stress will affect your physical condition more obviously too. Both will make symptoms worse.
Then there are the things which are almost impossible to identify. I had years where I hardly ate anything because I simply didn't ever feel hunger. I would faint all over the place from lack of food, but I didn't eat because unless I felt hungry I forgot or, if reminded, the thought of eating made me feel sick. This lasted for several years and I didn't realise there was anything wrong until one day I felt hungry. It was like a light dawning. I hadn't felt it for so long that I didn't immediately recognise it. That bit of my system works now, but it never occurred to me to tell my gp, or even my dh, as I forgot that that feeling existed.
Sometimes my eyes don't work properly; I have reading glasses which sometimes I don't need; conversely, sometimes I need them to be much stronger than they are. The prescription I get depends on bow my eyes are behaving on the day I have the appointment. Since January I have been quite deaf in my left ear. This has happened before, and at some point it will start working again.
Then there are the people like me who have relapsing/remitting ms (you have an attack but then you recover your lost ground given time - no telling how long though), but there's primary ms where the damage is permanent, and secondary ms where you started off with r/r but it's progressed so that your recovery is never full. In fact, that's me now - my neurologist told me last time I saw him.
The OP may well be perfectly coherent in her thoughts, her speech, but have difficulties controlling her hands or her fingers so she can't type accurately. She may not be able to read words on a screen as easily so that she cannot tell where or how to edit what she has typed - if she can get her hands to work properly in the first place. She may know exactly what she wants to say, but find that getting it down coherently is really hard. Any of these things, and a million more, could be laid at the door of ms, and can affect her coherence on screen.
(Sorry to talk about you as if you weren't there, op.)
Anyway, you can see that it is a hard thing to pin down.