J.T.
This is not uncommon. As will the respiratory infections/flu you become more suseptable to them due to a change in your immune system when pregnant. Your immune system shifts so your body does not abort the fetus. Normally, when the body detects something that is "not self", it immediately go on the attack to surround it and eliminate it. This would not be good for a fetus! So, the wisdom of this grand design we call the human body makes this shift in responses and the side effect as that we become more suseptable to getting sick. Ways that you can help yourself is by making sure your immune system get a little help. Get adequate vitamin D3 intake throughout your pregnancy--5000 I.U.'s per day. Take D3 on an empty stomach and don't eat for an hour after. Probiotics are extremely important as the majority of the immune system lies in the gut. Populating the gut with good flora with help keep the yuck away and also help with stearing clear of bladder infections. It's especially important since you have also been on a couple rounds of antibiotics as they have destroyed ALL your gut flora, not just the bad stuff which can make you more suseptable to subsequent infections. Also, omega-3's, at least 2000mg of fish oil per day is recommended as well as a high quality, whole food multi-vitamin.
Bladder infections are very common as the ureters expand to make up for the larger volume of blood during pregancy (up to 4 lbs more volume!). This allows an easier pathway for bacteria to get up into the bladder and kidneys. A supplement called D-Mannose, which is the active sugar in cranberries can help. D-Mannose creates a slippery environment that doesn't allow for the attachment of bacteria to your bladder and structures on down (that's what creates the burning feeling). So, when you go to the bathroom, you essentially pee them right out.
I have seen many pregnant women in my practice (and their babies!) and they all have done quite well with the supplement program that I have put them on. If you would like some more information concerning the professional supplements/vitamins I suggest (no MLM) just let me know.
Also, if you want some help with those nastly headaches, chiropractic is very safe and effective (especially during pregnancy) to help with all those body changes. It even has been shown to ease labor difficulties.
Send me a message and we can talk, I would love to help you through this wonderful time.