exhausted but can't sleep

i hate when i am this tired but i can't sleep because there are too  many issues on my mind...   lately i have been trying to concentrate only on my knee and therapy so i could walk in the 3K parkinsons walk on sept 19th...  i think i can do it.. my therapist does too..my whole family will walk with me so that's my incentive to keep pushing..problem isi have been pushing my self so hard by 7pm i am shaky and exhausted...i'm thinking maybe i should tell the neurologist but i really don't want a med change right before the walk it may make me tired...my knee is healing nicely i am not using a walker or even a cane... i can pick up my speed some now and today i walked areound the blook 4 times...  which i think is awesome... i have to get it increased to three k though i think that's a little over 2 miles....i'm staying with my daughter and really able to rehab here nicely so i think her for that...
One thing that is bothering me (and i hope to get some input here) is the whole reason i got my kneereplaced is so i could exercise because exercise is good for P'd...but as i am doing the exercises to recover for the knee i am working hard and bringing on the shakes so i'm sure we will up the meds... then my kneewill heal and i will exercise for the pd... but the prob get tremors so will haave to get med changed again so maybe even though everyonei guess what i'm saing is when it it stop... work hard... adjust... work hard... readjust...
thats all                     paula