Hi,
First, you can't determine your blood pressure from taking your pulse. Even if you could somehow determine your pulse pressure (sys minus dia), you can not know if your blood pressure is 100/60 or 150/110.
A high cardiac stroke volume will make your pulse harder, yes. But lots of other factors also matters, such as blood vessel dilation, the position of your arms, temperature, etc.
Sometimes my pulse is weak, sometimes it's strong. It doesn't really matter, and constantly checking this may make you turn into an OCD-ish condition. You need to break this cycle.
Blockages or a failing heart will not cause these symptoms, so you don't have to worry about that. The chance your heart is failing is not any higher than any 22 y/o, in other words negligible. Your problem is not your heart, it's your anxiety.
Have you been on a ecg (eck)? get it checked out xx
Did you find out why your heart started beating softer?? I have the same issue, my heart started beating a lot softer in like a month ago.