Congrats hun! Pregnancy tests are so accurate that doctors usually won't retest if you've a positive - you're far more likely to get a false negative than a false positive.

With exercising, you want to keep your body temp below 38.9 - so no hot spas / saunas etc. If you're fairly fit, then generally it's OK to maintain your current exercise level - just don't start training for any marathons or triathlons if you don't already do that

Start thinking about your maternity care though, do you want midwife care, GP care, or is there a family history where you think you may need an obstetrician? Either way, book in to see your GP soon as you'll need to get a referral for any tests required and a referral for an OB if you choose to go that way.

Congrats!