A good guide for knowing when to increase is to keep a log and jot down your dosage each day and take your body temp and your heart rate and jot that down. 3 pm is an ideal time to take temps but that can be hard to do if you are at work. So pick a time (sit down and relax for a few minutes before taking temps/heart rate) that is convenient and take it all at the same time each day. Also write down your dosage and how you are feeling. If body temp/heart rate are on the low side, you probably need to increase by 1/4 grain... track reaction ... and be ready to increase again in two weeks or so. Finding our 'sweet spot' (ideal dosage) can be a challenge sometimes.
Yes.. if too high, heart rate will increase and body temp may increase. You may feel flushy and have heart palps. As the other commenter mentioned, you can feel 'wired' or buzzed if at too high a dosage.