Joneser asked good questions regarding water and sleep.
Additionally, you mentioned you aren't lasting more than a few sets.
What exactly do you mean? Are you missing reps? Or just need to rest longer to get in your reps?
Here is my general training advice:
1. Rest at least 1 minute for this program. But you shouldn't have to rest more than 3 minutes or so to recover for the next step. (peak power output is 80% restored after 1 minute and 90% restored after 3 minutes so there actually isn't much benefit to resting too much longer than 1 minute)
2. Try to explode the weight up. Don't grind reps! Long term, you will feel much better if you train this way. It may mean lightening up the weight temporarily, but your CNS will thank you. Another benefit of lightening up the weight is that you will reinforce perfect technique (assuming you use perfect technique, i.e. form is mroe likely to break down if you are grinding reps)
3. Don't add weight until you can get all sets of 5 with clean, explosive reps. Than add weight.
4. Stick with this program and be patient, 5x5 is tried and true.
How long have you been at 195?
6'4" and 195 is pretty light. I'd feel safe saying you could probably up your carbs. Add in healthy carbs (rice, potatoes, veggies) preferable post workout. Also, considering adding dextrose to a workout shake if you aren't currently. Hard to get fat when you are taking in quality carbs around the workout window of opportunity.
If the scale starts to increase, than make sure you are making progress in the gym as well, otherwise you are just getting fat. Keep the bodyweight gains to around 1 pound every week or two.
James 1:16-17 ESV
Do not be deceived, my beloved brothers. Every good gift and every perfect gift is from above, coming down from the Father of lights
With God's help...Mens sana in corpore sano