Hi, I've been reading many articles on what to take / not to take while pregnant. My concern is what we should/should not be taking before we actually conceive?

Supplements Wise:
So far, my gynae has given me Prenatal vitamins (Prenaforte) which contains Folic Acid which is supposed to be good for the baby . On top of that, I have been taking 1000mg of Vitamin C just to keep the immune system strong and to avoid falling ill during this time.

Medication Wise:
Another big concern of mine is whether I should be taking other forms of medication for example:
- I've been using Steroid Cream to treat my Eczema
- Eye Drops to treat my eyes after recent LASIK procedure (PRED Forte & Vigamox).
I have taken the liberty to google these drugs and they are classified as Cat C medication (definition: Animal reproduction studies have shown an adverse effect on the fetus and there are no adequate and well-controlled studies in humans, but potential benefits may warrant use of the drug in pregnant women despite potential risks.).

My question is, whether or not taking these sort of medication can still affect the fetus if say I conceive in 1 month's time. Should I already be trying to avoid taking such medication? Perhaps I am a little paranoid but would appreciate some advice!