You can be strong and still experience suffering.
You can be grateful and still experience grief.
It is normal, and it is okay. Both are sides of the experience are important and necessary.
A common question after catastrophes like Hurricane Harvey is about trauma and PTSD. The first thing I talk about is how normal it is to have emotional responses to reminders within the first few weeks following a traumatic event. People often would prefer to avoid certain places or have a heightened emotional response to an everyday experience, like going to sleep, checking your phone, watching the news, or listening to the rain. Within the first few weeks after an event, it is normal and natural to have these reactions. As you proceed through your life, they typically fade away within a month or so. If you continue to engage in the avoided or emotional activities it is more likely to fade, and fade faster the more you do those things.
If they do not fade within a month, then it may be helpful to talk to a professional about it. Traumatic stress symptoms are very treatable, and the sooner you can treat them, the better.
More common than traumatic stress reactions in some cases though is depression. Depression caused by chronic stress or by pain and sadness that got stuck.
Some people have difficulty tolerating emotions such as suffering and grief, with some turning to substances or problematic behaviors (such as over-working, addictive or compulsive behaviors) to not have to feel the feelings. This digs the hole even deeper. Putting the pain off does not make it go away. Giving yourself permission to be sad and grieve helps. Talking to a professional about these issues is a good idea so that you can feel the pain and let it wash away rather exhausting yourself trying to push them away.
In a different way, some people keep busy cleaning and moving and saying how grateful they are to be safe, so that they don't have to feel the loss, the sadness, the grief. The loss is enormous and deserves to be acknowledged, just as much as the things you are grateful for. You cannot simply paint over grief with gratitude in the same way you can't just paint over sopping wet drywall. You have to clear out the room, pull up the floors, look at how much needs to be cut, and piece by piece, take down the drywall and insulation behind before putting up new drywall and moving on. So too there is emotional work. Grieving fully all that is lost, materially and immaterially. Each memento lost and each object that provided comfort or security matters and will have a felt impact. Loss of comfort, security, and routine matter. Chances are, within the first week you cried for your city, for your friends and family, for yourself. Know that it is okay. Know that it is necessary.
Like the financial toll, it is too soon to say what the real psychological toll of Hurricane Harvey will be on Houston, but there is and will continue to be overwhelming suffering and sadness. Allow it to be felt until it no longer needs to be felt. That requires the strength of being truly Texas and Houston Strong.